1 /*
2 * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
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20 * or visit www.oracle.com if you need additional information or have any
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23 */
24
25 #ifndef SHARE_RUNTIME_GLOBALS_HPP
26 #define SHARE_RUNTIME_GLOBALS_HPP
27
28 #include "compiler/compiler_globals_pd.hpp"
29 #include "runtime/globals_shared.hpp"
30 #include "utilities/align.hpp"
31 #include "utilities/globalDefinitions.hpp"
32 #include "utilities/macros.hpp"
33 #include CPU_HEADER(globals)
34 #include OS_HEADER(globals)
35 #include OS_CPU_HEADER(globals)
36
37 // develop flags are settable / visible only during development and are constant in the PRODUCT version
38 // product flags are always settable / visible
39 // develop_pd/product_pd flags are the same as develop/product, except that their default values
40 // are specified in platform-dependent header files.
41
42 // Flags must be declared with the following number of parameters:
43 // non-pd flags:
44 // (type, name, default_value, doc), or
45 // (type, name, default_value, extra_attrs, doc)
46 // pd flags:
47 // (type, name, doc), or
48 // (type, name, extra_attrs, doc)
49
50 // A flag must be declared with one of the following types:
51 // bool, int, uint, intx, uintx, size_t, ccstr, ccstrlist, double, or uint64_t.
52 // The type "ccstr" and "ccstrlist" are an alias for "const char*" and is used
53 // only in this file, because the macrology requires single-token type names.
54
55 // The optional extra_attrs parameter may have one of the following values:
56 // DIAGNOSTIC, EXPERIMENTAL, or MANAGEABLE. Currently extra_attrs can be used
57 // only with product/product_pd flags.
58 //
59 // DIAGNOSTIC options are not meant for VM tuning or for product modes.
60 // They are to be used for VM quality assurance or field diagnosis
61 // of VM bugs. They are hidden so that users will not be encouraged to
62 // try them as if they were VM ordinary execution options. However, they
63 // are available in the product version of the VM. Under instruction
64 // from support engineers, VM customers can turn them on to collect
65 // diagnostic information about VM problems. To use a VM diagnostic
66 // option, you must first specify +UnlockDiagnosticVMOptions.
67 // (This master switch also affects the behavior of -Xprintflags.)
68 //
69 // EXPERIMENTAL flags are in support of features that may not be
70 // an officially supported part of a product, but may be available
71 // for experimenting with. They could, for example, be performance
72 // features that may not have undergone full or rigorous QA, but which may
73 // help performance in some cases and released for experimentation
74 // by the community of users and developers. This flag also allows one to
75 // be able to build a fully supported product that nonetheless also
76 // ships with some unsupported, lightly tested, experimental features.
77 // Refer to the documentation of any products using this code for details
78 // on support and fitness for production.
79 // Like the UnlockDiagnosticVMOptions flag above, there is a corresponding
80 // UnlockExperimentalVMOptions flag, which allows the control and
81 // modification of the experimental flags.
82 //
83 // Nota bene: neither diagnostic nor experimental options should be used casually,
84 // Refer to the documentation of any products using this code for details.
85 //
86 // MANAGEABLE flags are writeable external product flags.
87 // They are dynamically writeable through the JDK management interface
88 // (com.sun.management.HotSpotDiagnosticMXBean API) and also through JConsole.
89 // These flags are external exported interface (see CSR). The list of
90 // manageable flags can be queried programmatically through the management
91 // interface.
92 //
93 // A flag can be made as "manageable" only if
94 // - the flag is defined in a CSR request as an external exported interface.
95 // - the VM implementation supports dynamic setting of the flag.
96 // This implies that the VM must *always* query the flag variable
97 // and not reuse state related to the flag state at any given time.
98 // - you want the flag to be queried programmatically by the customers.
99 //
100
101 //
102 // range is a macro that will expand to min and max arguments for range
103 // checking code if provided - see jvmFlagLimit.hpp
104 //
105 // constraint is a macro that will expand to custom function call
106 // for constraint checking if provided - see jvmFlagLimit.hpp
107
108 // Default and minimum StringTable and SymbolTable size values
109 // Must be powers of 2
110 const size_t defaultStringTableSize = NOT_LP64(1024) LP64_ONLY(65536);
111 const size_t minimumStringTableSize = 128;
112 const size_t defaultSymbolTableSize = 32768; // 2^15
113 const size_t minimumSymbolTableSize = 1024;
114
115 #ifdef _LP64
116 #define LP64_RUNTIME_FLAGS(develop, \
117 develop_pd, \
118 product, \
119 product_pd, \
120 range, \
121 constraint) \
122 \
123 product(bool, UseCompressedOops, false, \
124 "Use 32-bit object references in 64-bit VM. " \
125 "lp64_product means flag is always constant in 32 bit VM") \
126 \
127 product(bool, AOTCompatibleOopCompression, false, DIAGNOSTIC, \
128 "Always use HeapBasedNarrowOop mode, so that AOT code will " \
129 "always work regardless of runtime heap range") \
130 \
131 product(bool, UseCompactObjectHeaders, true, \
132 "Use compact 64-bit object headers in 64-bit VM") \
133 \
134 product(int, ObjectAlignmentInBytes, 8, \
135 "Default object alignment in bytes, 8 is minimum") \
136 range(8, 256) \
137 constraint(ObjectAlignmentInBytesConstraintFunc, AtParse)
138
139 #else
140 // !_LP64
141
142 #define LP64_RUNTIME_FLAGS(develop, \
143 develop_pd, \
144 product, \
145 product_pd, \
146 range, \
147 constraint)
148 const bool UseCompressedOops = false;
149 const bool AOTCompatibleOopCompression = false;
150 const bool UseCompactObjectHeaders = false;
151 const int ObjectAlignmentInBytes = 8;
152
153 #endif // _LP64
154
155 // Default value for PrintAssemblyOptions, set via --with-print-assembly-options.
156 #ifndef DEFAULT_PRINT_ASSEMBLY_OPTIONS
157 #define DEFAULT_PRINT_ASSEMBLY_OPTIONS nullptr
158 #endif
159
160 #define RUNTIME_FLAGS(develop, \
161 develop_pd, \
162 product, \
163 product_pd, \
164 range, \
165 constraint) \
166 \
167 develop(bool, CheckCompressedOops, true, \
168 "Generate checks in encoding/decoding code in debug VM") \
169 \
170 product(uintx, HeapSearchSteps, 3 PPC64_ONLY(+17), \
171 "Heap allocation steps through preferred address regions to find" \
172 " where it can allocate the heap. Number of steps to take per " \
173 "region.") \
174 range(1, max_uintx) \
175 \
176 product(uint, HandshakeTimeout, 0, DIAGNOSTIC, \
177 "If nonzero set a timeout in milliseconds for handshakes") \
178 \
179 product(bool, AlwaysSafeConstructors, false, EXPERIMENTAL, \
180 "Force safe construction, as if all fields are final.") \
181 \
182 product(bool, UnlockDiagnosticVMOptions, trueInDebug, DIAGNOSTIC, \
183 "Enable normal processing of flags relating to field diagnostics")\
184 \
185 product(bool, UnlockExperimentalVMOptions, false, EXPERIMENTAL, \
186 "Enable normal processing of flags relating to experimental " \
187 "features") \
188 \
189 product(bool, JavaMonitorsInStackTrace, true, \
190 "Print information about Java monitor locks when the stacks are " \
191 "dumped") \
192 \
193 product_pd(bool, UseLargePages, \
194 "Use large page memory") \
195 \
196 product_pd(bool, UseLargePagesIndividualAllocation, \
197 "Allocate large pages individually for better affinity") \
198 \
199 develop(bool, LargePagesIndividualAllocationInjectError, false, \
200 "Fail large pages individual allocation") \
201 \
202 product(bool, UseNUMA, false, \
203 "Use NUMA if available") \
204 \
205 product(bool, UseNUMAInterleaving, false, \
206 "Interleave memory across NUMA nodes if available") \
207 \
208 product(size_t, NUMAInterleaveGranularity, 2*M, \
209 "Granularity to use for NUMA interleaving on Windows OS") \
210 constraint(NUMAInterleaveGranularityConstraintFunc, AtParse) \
211 \
212 product(bool, NUMAStats, false, \
213 "Print NUMA stats in detailed heap information") \
214 \
215 product(bool, UseAES, false, \
216 "Control whether AES instructions are used when available") \
217 \
218 product(bool, UseFMA, false, \
219 "Control whether FMA instructions are used when available") \
220 \
221 product(bool, UseSHA, false, \
222 "Control whether SHA instructions are used when available") \
223 \
224 product(bool, UseGHASHIntrinsics, false, DIAGNOSTIC, \
225 "Use intrinsics for GHASH versions of crypto") \
226 \
227 product(bool, UseBASE64Intrinsics, false, \
228 "Use intrinsics for java.util.Base64") \
229 \
230 product(bool, UsePoly1305Intrinsics, false, DIAGNOSTIC, \
231 "Use intrinsics for sun.security.util.math.intpoly") \
232 \
233 product(bool, UseIntPolyIntrinsics, false, DIAGNOSTIC, \
234 "Use intrinsics for sun.security.util.math.intpoly.MontgomeryIntegerPolynomialP256") \
235 \
236 product(bool, UseIntPoly25519Intrinsics, false, DIAGNOSTIC, \
237 "Use intrinsics for sun.security.util.math.intpoly.IntegerPolynomial25519") \
238 \
239 product(size_t, LargePageSizeInBytes, 0, \
240 "Maximum large page size used (0 will use the default large " \
241 "page size for the environment as the maximum) " \
242 "(must be a power of 2)") \
243 range(0, max_uintx) \
244 constraint(LargePageSizeInBytesConstraintFunc, AtParse) \
245 \
246 product(size_t, LargePageHeapSizeThreshold, 128*M, \
247 "Use large pages if maximum heap is at least this big") \
248 range(0, max_uintx) \
249 \
250 product(bool, ForceTimeHighResolution, false, \
251 "Using high time resolution (for Win32 only)") \
252 \
253 develop(bool, TracePcPatching, false, \
254 "Trace usage of frame::patch_pc") \
255 \
256 product(bool, SafepointALot, false, DIAGNOSTIC, \
257 "Generate a lot of safepoints. This works with " \
258 "GuaranteedSafepointInterval") \
259 \
260 product(bool, HandshakeALot, false, DIAGNOSTIC, \
261 "Generate a lot of handshakes. This works with " \
262 "GuaranteedSafepointInterval") \
263 \
264 product_pd(bool, BackgroundCompilation, \
265 "A thread requesting compilation is not blocked during " \
266 "compilation") \
267 \
268 product(bool, MethodFlushing, true, \
269 "Reclamation of compiled methods") \
270 \
271 develop(bool, VerifyStack, false, \
272 "Verify stack of each thread when it is entering a runtime call") \
273 \
274 product(bool, ForceUnreachable, false, DIAGNOSTIC, \
275 "Make all non code cache addresses to be unreachable by " \
276 "forcing use of 64bit literal fixups") \
277 \
278 develop(bool, TraceDerivedPointers, false, \
279 "Trace traversal of derived pointers on stack") \
280 \
281 develop(bool, TraceCodeBlobStacks, false, \
282 "Trace stack-walk of codeblobs") \
283 \
284 product(bool, UseInlineCaches, true, \
285 "Use Inline Caches for virtual calls ") \
286 \
287 develop(bool, VerifyInlineCaches, true, \
288 "Verify Inline Caches") \
289 \
290 product(bool, InlineArrayCopy, true, DIAGNOSTIC, \
291 "Inline arraycopy native that is known to be part of " \
292 "base library DLL") \
293 \
294 product(bool, InlineObjectHash, true, DIAGNOSTIC, \
295 "Inline Object::hashCode() native that is known to be part " \
296 "of base library DLL") \
297 \
298 product(bool, InlineNatives, true, DIAGNOSTIC, \
299 "Inline natives that are known to be part of base library DLL") \
300 \
301 product(bool, InlineMathNatives, true, DIAGNOSTIC, \
302 "Inline SinD, CosD, etc.") \
303 \
304 product(bool, InlineClassNatives, true, DIAGNOSTIC, \
305 "Inline Class.isInstance, etc") \
306 \
307 product(bool, InlineThreadNatives, true, DIAGNOSTIC, \
308 "Inline Thread.currentThread, etc") \
309 \
310 product(bool, InlineUnsafeOps, true, DIAGNOSTIC, \
311 "Inline memory ops (native methods) from Unsafe") \
312 \
313 product(bool, UseAESIntrinsics, false, DIAGNOSTIC, \
314 "Use intrinsics for AES versions of crypto") \
315 \
316 product(bool, UseAESCTRIntrinsics, false, DIAGNOSTIC, \
317 "Use intrinsics for the paralleled version of AES/CTR crypto") \
318 \
319 product(bool, UseChaCha20Intrinsics, false, DIAGNOSTIC, \
320 "Use intrinsics for the vectorized version of ChaCha20") \
321 \
322 product(bool, UseKyberIntrinsics, false, DIAGNOSTIC, \
323 "Use intrinsics for the vectorized version of Kyber") \
324 \
325 product(bool, UseDilithiumIntrinsics, false, DIAGNOSTIC, \
326 "Use intrinsics for the vectorized version of Dilithium") \
327 \
328 product(bool, UseMD5Intrinsics, false, DIAGNOSTIC, \
329 "Use intrinsics for MD5 crypto hash function") \
330 \
331 product(bool, UseSHA1Intrinsics, false, DIAGNOSTIC, \
332 "Use intrinsics for SHA-1 crypto hash function. " \
333 "Requires that UseSHA is enabled.") \
334 \
335 product(bool, UseSHA256Intrinsics, false, DIAGNOSTIC, \
336 "Use intrinsics for SHA-224 and SHA-256 crypto hash functions. " \
337 "Requires that UseSHA is enabled.") \
338 \
339 product(bool, UseSHA512Intrinsics, false, DIAGNOSTIC, \
340 "Use intrinsics for SHA-384 and SHA-512 crypto hash functions. " \
341 "Requires that UseSHA is enabled.") \
342 \
343 product(bool, UseSHA3Intrinsics, false, DIAGNOSTIC, \
344 "Use intrinsics for SHA3 crypto hash function. " \
345 "Requires that UseSHA is enabled.") \
346 \
347 product(bool, UseCRC32Intrinsics, false, DIAGNOSTIC, \
348 "use intrinsics for java.util.zip.CRC32") \
349 \
350 product(bool, UseCRC32CIntrinsics, false, DIAGNOSTIC, \
351 "use intrinsics for java.util.zip.CRC32C") \
352 \
353 product(bool, UseAdler32Intrinsics, false, DIAGNOSTIC, \
354 "use intrinsics for java.util.zip.Adler32") \
355 \
356 product(bool, UseVectorizedMismatchIntrinsic, false, DIAGNOSTIC, \
357 "Enables intrinsification of ArraysSupport.vectorizedMismatch()") \
358 \
359 product(bool, UseVectorizedHashCodeIntrinsic, false, DIAGNOSTIC, \
360 "Enables intrinsification of ArraysSupport.vectorizedHashCode()") \
361 \
362 product(bool, UseCopySignIntrinsic, false, DIAGNOSTIC, \
363 "Enables intrinsification of Math.copySign") \
364 \
365 product(bool, UseSignumIntrinsic, false, DIAGNOSTIC, \
366 "Enables intrinsification of Math.signum") \
367 \
368 product_pd(bool, DelayCompilerStubsGeneration, DIAGNOSTIC, \
369 "Use Compiler thread for compiler's stubs generation") \
370 \
371 product(ccstrlist, DisableIntrinsic, "", DIAGNOSTIC, \
372 "do not expand intrinsics whose (internal) names appear here") \
373 constraint(DisableIntrinsicConstraintFunc,AfterErgo) \
374 \
375 product(ccstrlist, ControlIntrinsic, "", DIAGNOSTIC, \
376 "Control intrinsics using a list of +/- (internal) names, " \
377 "separated by commas") \
378 constraint(ControlIntrinsicConstraintFunc,AfterErgo) \
379 \
380 develop(bool, TraceCallFixup, false, \
381 "Trace all call fixups") \
382 \
383 develop(bool, DeoptimizeALot, false, \
384 "Deoptimize at every exit from the runtime system") \
385 \
386 develop(ccstrlist, DeoptimizeOnlyAt, "", \
387 "A comma separated list of bcis to deoptimize at") \
388 \
389 develop(bool, DeoptimizeRandom, false, \
390 "Deoptimize random frames on random exit from the runtime system")\
391 \
392 develop(bool, ZombieALot, false, \
393 "Create non-entrant nmethods at exit from the runtime system") \
394 \
395 develop(bool, WalkStackALot, false, \
396 "Trace stack (no print) at every exit from the runtime system") \
397 \
398 develop(bool, DeoptimizeObjectsALot, false, \
399 "For testing purposes concurrent threads revert optimizations " \
400 "based on escape analysis at intervals given with " \
401 "DeoptimizeObjectsALotInterval=n. The thread count is given " \
402 "with DeoptimizeObjectsALotThreadCountSingle and " \
403 "DeoptimizeObjectsALotThreadCountAll.") \
404 \
405 develop(uint64_t, DeoptimizeObjectsALotInterval, 5, \
406 "Interval for DeoptimizeObjectsALot.") \
407 range(0, max_jlong) \
408 \
409 develop(int, DeoptimizeObjectsALotThreadCountSingle, 1, \
410 "The number of threads that revert optimizations based on " \
411 "escape analysis for a single thread if DeoptimizeObjectsALot " \
412 "is enabled. The target thread is selected round robin." ) \
413 range(0, max_jint) \
414 \
415 develop(int, DeoptimizeObjectsALotThreadCountAll, 1, \
416 "The number of threads that revert optimizations based on " \
417 "escape analysis for all threads if DeoptimizeObjectsALot " \
418 "is enabled." ) \
419 range(0, max_jint) \
420 \
421 develop(bool, VerifyLastFrame, false, \
422 "Verify oops on last frame on entry to VM") \
423 \
424 product(bool, SafepointTimeout, false, \
425 "Time out and warn or fail after SafepointTimeoutDelay " \
426 "milliseconds if failed to reach safepoint") \
427 \
428 product(bool, AbortVMOnSafepointTimeout, false, DIAGNOSTIC, \
429 "Abort upon failure to reach safepoint (see SafepointTimeout)") \
430 \
431 product(uint64_t, AbortVMOnSafepointTimeoutDelay, 0, DIAGNOSTIC, \
432 "Delay in milliseconds for option AbortVMOnSafepointTimeout") \
433 range(0, max_jlong) \
434 \
435 product(bool, AbortVMOnVMOperationTimeout, false, DIAGNOSTIC, \
436 "Abort upon failure to complete VM operation promptly") \
437 \
438 product(intx, AbortVMOnVMOperationTimeoutDelay, 1000, DIAGNOSTIC, \
439 "Delay in milliseconds for option AbortVMOnVMOperationTimeout") \
440 range(0, max_intx) \
441 \
442 product(bool, MaxFDLimit, true, \
443 "Bump the number of file descriptors to maximum (Unix only)") \
444 \
445 product(bool, LogEvents, true, DIAGNOSTIC, \
446 "Enable the various ring buffer event logs") \
447 \
448 product(int, LogEventsBufferEntries, 20, DIAGNOSTIC, \
449 "Number of ring buffer event logs") \
450 range(1, NOT_LP64(1*K) LP64_ONLY(1*M)) \
451 \
452 product(bool, BytecodeVerificationRemote, true, DIAGNOSTIC, \
453 "Enable the Java bytecode verifier for remote classes") \
454 \
455 product(bool, BytecodeVerificationLocal, false, DIAGNOSTIC, \
456 "Enable the Java bytecode verifier for local classes") \
457 \
458 develop(bool, VerifyStackAtCalls, false, \
459 "Verify that the stack pointer is unchanged after calls") \
460 \
461 develop(bool, VerifyCodeCache, false, \
462 "Verify code cache on memory allocation/deallocation") \
463 \
464 develop(bool, ZapResourceArea, trueInDebug, \
465 "Zap freed resource/arena space") \
466 \
467 develop(bool, ZapVMHandleArea, trueInDebug, \
468 "Zap freed VM handle space") \
469 \
470 develop(bool, ZapStackSegments, trueInDebug, \
471 "Zap allocated/freed stack segments") \
472 \
473 develop(bool, ZapUnusedHeapArea, trueInDebug, \
474 "Zap unused heap space") \
475 \
476 develop(bool, ZapFillerObjects, trueInDebug, \
477 "Zap filler objects") \
478 \
479 develop(bool, ZapCHeap, trueInDebug, \
480 "Zap allocated/freed C heap space") \
481 \
482 develop(bool, ZapTLAB, trueInDebug, \
483 "Zap allocated TLABs") \
484 develop(bool, TestingAsyncLoggingDeathTest, false, \
485 "Recursive logging death test") \
486 develop(bool, TestingAsyncLoggingDeathTestNoCrash, false, \
487 "Recursive logging death test (no crash)") \
488 \
489 product(bool, ExecutingUnitTests, false, \
490 "Whether the JVM is running unit tests or not") \
491 \
492 develop(uint, ErrorHandlerTest, 0, \
493 "If > 0, provokes an error after VM initialization; the value " \
494 "determines which error to provoke. See controlled_crash() " \
495 "in vmError.cpp.") \
496 range(0, 18) \
497 \
498 develop(uint, TestCrashInErrorHandler, 0, \
499 "If > 0, provokes an error inside VM error handler (a secondary " \
500 "crash). see controlled_crash() in vmError.cpp") \
501 range(0, 17) \
502 \
503 develop(bool, TestSafeFetchInErrorHandler, false , \
504 "If true, tests SafeFetch inside error handler.") \
505 \
506 develop(bool, TestUnresponsiveErrorHandler, false, \
507 "If true, simulates an unresponsive error handler.") \
508 \
509 develop(bool, Verbose, false, \
510 "Print additional debugging information from other modes") \
511 \
512 develop(bool, PrintMiscellaneous, false, \
513 "Print uncategorized debugging information (requires +Verbose)") \
514 \
515 develop(bool, WizardMode, false, \
516 "Print much more debugging information") \
517 \
518 product(bool, ShowMessageBoxOnError, false, \
519 "Keep process alive on VM fatal error") \
520 \
521 product(bool, CreateCoredumpOnCrash, true, \
522 "Create core/mini dump on VM fatal error") \
523 \
524 product(uint64_t, ErrorLogTimeout, 2 * 60, \
525 "Timeout, in seconds, to limit the time spent on writing an " \
526 "error log in case of a crash.") \
527 range(0, (uint64_t)max_jlong/1000) \
528 \
529 product(bool, ErrorLogSecondaryErrorDetails, false, DIAGNOSTIC, \
530 "If enabled, show details on secondary crashes in the error log") \
531 \
532 develop(intx, TraceDwarfLevel, 0, \
533 "Debug levels for the dwarf parser") \
534 range(0, 4) \
535 \
536 product(bool, SuppressFatalErrorMessage, false, \
537 "Report NO fatal error message (avoid deadlock)") \
538 \
539 product(ccstrlist, OnError, "", \
540 "Run user-defined commands on fatal error; see VMError.cpp " \
541 "for examples") \
542 \
543 product(ccstrlist, OnOutOfMemoryError, "", \
544 "Run user-defined commands on first java.lang.OutOfMemoryError " \
545 "thrown from JVM") \
546 \
547 product(bool, HeapDumpBeforeFullGC, false, MANAGEABLE, \
548 "Dump heap to file before any major stop-the-world GC " \
549 "(also see FullGCHeapDumpLimit, HeapDumpPath, HeapDumpGzipLevel)")\
550 \
551 product(bool, HeapDumpAfterFullGC, false, MANAGEABLE, \
552 "Dump heap to file after any major stop-the-world GC " \
553 "(also see FullGCHeapDumpLimit, HeapDumpPath, HeapDumpGzipLevel)")\
554 \
555 product(uint, FullGCHeapDumpLimit, 0, MANAGEABLE, \
556 "Limit the number of heap dumps triggered by " \
557 "HeapDumpBeforeFullGC or HeapDumpAfterFullGC " \
558 "(0 means no limit)") \
559 \
560 product(bool, HeapDumpOnOutOfMemoryError, false, MANAGEABLE, \
561 "Dump heap to file when java.lang.OutOfMemoryError is thrown " \
562 "from JVM " \
563 "(also see HeapDumpPath, HeapDumpGzipLevel)") \
564 \
565 product(ccstr, HeapDumpPath, nullptr, MANAGEABLE, \
566 "When HeapDumpOnOutOfMemoryError, HeapDumpBeforeFullGC " \
567 "or HeapDumpAfterFullGC is on, the path (filename or " \
568 "directory) of the dump file (defaults to java_pid<pid>.hprof " \
569 "in the working directory)") \
570 \
571 product(int, HeapDumpGzipLevel, 0, MANAGEABLE, \
572 "When HeapDumpOnOutOfMemoryError, HeapDumpBeforeFullGC " \
573 "or HeapDumpAfterFullGC is on, the gzip compression " \
574 "level of the dump file. 0 (the default) disables gzip " \
575 "compression. Otherwise the level must be between 1 and 9.") \
576 range(0, 9) \
577 \
578 product(ccstr, NativeMemoryTracking, DEBUG_ONLY("summary") NOT_DEBUG("off"), \
579 "Native memory tracking options") \
580 \
581 product(bool, PrintNMTStatistics, false, DIAGNOSTIC, \
582 "Print native memory tracking summary data if it is on") \
583 \
584 product(bool, LogCompilation, false, DIAGNOSTIC, \
585 "Log compilation activity in detail to LogFile") \
586 \
587 product(bool, PrintCompilation, false, \
588 "Print compilations") \
589 \
590 product(intx, RepeatCompilation, 0, DIAGNOSTIC, \
591 "Repeat compilation without installing code (number of times)") \
592 range(0, max_jint) \
593 \
594 product(bool, PrintExtendedThreadInfo, false, \
595 "Print more information in thread dump") \
596 \
597 product(intx, ScavengeRootsInCode, 2, DIAGNOSTIC, \
598 "0: do not allow scavengable oops in the code cache; " \
599 "1: allow scavenging from the code cache; " \
600 "2: emit as many constants as the compiler can see") \
601 range(0, 2) \
602 \
603 product(bool, AlwaysRestoreFPU, false, \
604 "Restore the FPU control word after every JNI call (expensive)") \
605 \
606 product(bool, PrintCompilation2, false, DIAGNOSTIC, \
607 "Print additional statistics per compilation") \
608 \
609 product(bool, PrintAdapterHandlers, false, DIAGNOSTIC, \
610 "Print code generated for i2c/c2i adapters") \
611 \
612 develop(bool, VerifyAdapterSharing, false, \
613 "Verify that the code for shared adapters is the equivalent") \
614 \
615 product(bool, PrintAssembly, false, DIAGNOSTIC, \
616 "Print assembly code (using external disassembler.so)") \
617 \
618 product(ccstr, PrintAssemblyOptions, DEFAULT_PRINT_ASSEMBLY_OPTIONS, \
619 DIAGNOSTIC, \
620 "Print options string passed to disassembler.so") \
621 \
622 develop(bool, PrintNMethodStatistics, false, \
623 "Print a summary statistic for the generated nmethods") \
624 \
625 product(bool, PrintNMethods, false, DIAGNOSTIC, \
626 "Print assembly code for nmethods when generated") \
627 \
628 product(bool, PrintNativeNMethods, false, DIAGNOSTIC, \
629 "Print assembly code for native nmethods when generated") \
630 \
631 develop(bool, PrintDebugInfo, false, \
632 "Print debug information for all nmethods when generated") \
633 \
634 develop(bool, PrintRelocations, false, \
635 "Print relocation information for all nmethods when generated") \
636 \
637 develop(bool, PrintDependencies, false, \
638 "Print dependency information for all nmethods when generated") \
639 \
640 develop(bool, PrintExceptionHandlers, false, \
641 "Print exception handler tables for all nmethods when generated") \
642 \
643 develop(bool, StressCompiledExceptionHandlers, false, \
644 "Exercise compiled exception handlers") \
645 \
646 product(bool, DeoptimizeOnAllocationException, false, DIAGNOSTIC, \
647 "Deoptimize on exception during allocation instead of using the " \
648 "compiled exception handlers") \
649 \
650 develop(bool, InterceptOSException, false, \
651 "Start debugger when an implicit OS (e.g. null pointer) " \
652 "exception happens") \
653 \
654 product(bool, PrintCodeCache, false, \
655 "Print the code cache memory usage when exiting") \
656 \
657 develop(bool, PrintCodeCache2, false, \
658 "Print detailed usage information on the code cache when exiting")\
659 \
660 product(bool, PrintCodeCacheOnCompilation, false, \
661 "Print the code cache memory usage each time a method is " \
662 "compiled") \
663 \
664 product(bool, PrintCodeHeapAnalytics, false, DIAGNOSTIC, \
665 "Print code heap usage statistics on exit and on full condition") \
666 \
667 product(bool, PrintStubCode, false, DIAGNOSTIC, \
668 "Print generated stub code") \
669 \
670 product(bool, StackTraceInThrowable, true, \
671 "Collect backtrace in throwable when exception happens") \
672 \
673 product(bool, OmitStackTraceInFastThrow, true, \
674 "Omit backtraces for some 'hot' exceptions in optimized code") \
675 \
676 product(bool, ShowCodeDetailsInExceptionMessages, true, MANAGEABLE, \
677 "Show exception messages from RuntimeExceptions that contain " \
678 "snippets of the failing code. Disable this to improve privacy.") \
679 \
680 product(bool, PrintWarnings, true, \
681 "Print JVM warnings to output stream") \
682 \
683 develop(bool, RegisterReferences, true, \
684 "Tell whether the VM should register soft/weak/final/phantom " \
685 "references") \
686 \
687 develop(bool, PrintCodeCacheExtension, false, \
688 "Print extension of code cache") \
689 \
690 product(bool, ClassUnloading, true, \
691 "Do unloading of classes") \
692 \
693 product(bool, ClassUnloadingWithConcurrentMark, true, \
694 "Do unloading of classes with a concurrent marking cycle") \
695 \
696 develop(bool, PrintSystemDictionaryAtExit, false, \
697 "Print the system dictionary at exit") \
698 \
699 develop(bool, PrintClassLoaderDataGraphAtExit, false, \
700 "Print the class loader data graph at exit") \
701 \
702 product(bool, PrintVMInfoAtExit, false, DIAGNOSTIC, \
703 "Executes the VM.info diagnostic command at exit") \
704 \
705 product(bool, AllowParallelDefineClass, false, \
706 "Allow parallel defineClass requests for class loaders " \
707 "registering as parallel capable") \
708 \
709 product(bool, DisablePrimordialThreadGuardPages, false, EXPERIMENTAL, \
710 "Disable the use of stack guard pages if the JVM is loaded " \
711 "on the primordial process thread") \
712 \
713 product(bool, DoJVMTIVirtualThreadTransitions, true, EXPERIMENTAL, \
714 "Do JVMTI virtual thread mount/unmount transitions " \
715 "(disabling this flag implies no JVMTI events are posted)") \
716 \
717 /* notice: the max range value here is max_jint, not max_intx */ \
718 /* because of overflow issue */ \
719 product(intx, AsyncDeflationInterval, 250, DIAGNOSTIC, \
720 "Async deflate idle monitors every so many milliseconds when " \
721 "MonitorUsedDeflationThreshold is exceeded (0 is off).") \
722 range(0, max_jint) \
723 \
724 /* notice: the max range value here is max_jint, not max_intx */ \
725 /* because of overflow issue */ \
726 product(intx, GuaranteedAsyncDeflationInterval, 60000, DIAGNOSTIC, \
727 "Async deflate idle monitors every so many milliseconds even " \
728 "when MonitorUsedDeflationThreshold is NOT exceeded (0 is off).") \
729 range(0, max_jint) \
730 \
731 product(size_t, AvgMonitorsPerThreadEstimate, 1024, DIAGNOSTIC, \
732 "Used to estimate a variable ceiling based on number of threads " \
733 "for use with MonitorUsedDeflationThreshold (0 is off).") \
734 range(0, max_uintx) \
735 \
736 /* notice: the max range value here is max_jint, not max_intx */ \
737 /* because of overflow issue */ \
738 product(intx, MonitorDeflationMax, 1000000, DIAGNOSTIC, \
739 "The maximum number of monitors to deflate, unlink and delete " \
740 "at one time (minimum is 1024).") \
741 range(1024, max_jint) \
742 \
743 product(intx, MonitorUnlinkBatch, 500, DIAGNOSTIC, \
744 "The maximum number of monitors to unlink in one batch. ") \
745 range(1, max_jint) \
746 \
747 product(int, MonitorUsedDeflationThreshold, 90, DIAGNOSTIC, \
748 "Percentage of used monitors before triggering deflation (0 is " \
749 "off). The check is performed on AsyncDeflationInterval or " \
750 "GuaranteedAsyncDeflationInterval, whichever is lower.") \
751 range(0, 100) \
752 \
753 product(uintx, NoAsyncDeflationProgressMax, 3, DIAGNOSTIC, \
754 "Max number of no progress async deflation attempts to tolerate " \
755 "before adjusting the in_use_list_ceiling up (0 is off).") \
756 range(0, max_uintx) \
757 \
758 product(intx, hashCode, 5, EXPERIMENTAL, \
759 "(Unstable) select hashCode generation algorithm") \
760 \
761 product(bool, ReduceSignalUsage, false, \
762 "Reduce the use of OS signals in Java and/or the VM") \
763 \
764 develop(bool, LoadLineNumberTables, true, \
765 "Tell whether the class file parser loads line number tables") \
766 \
767 develop(bool, LoadLocalVariableTables, true, \
768 "Tell whether the class file parser loads local variable tables") \
769 \
770 develop(bool, LoadLocalVariableTypeTables, true, \
771 "Tell whether the class file parser loads local variable type" \
772 "tables") \
773 \
774 product(bool, AllowUserSignalHandlers, false, \
775 "Application will install primary signal handlers for the JVM " \
776 "(Unix only)") \
777 \
778 product(bool, UseSignalChaining, true, \
779 "Use signal-chaining to invoke signal handlers installed " \
780 "by the application (Unix only)") \
781 \
782 product(bool, RestoreMXCSROnJNICalls, false, \
783 "Restore MXCSR when returning from JNI calls") \
784 \
785 product(bool, CheckJNICalls, false, \
786 "Verify all arguments to JNI calls") \
787 \
788 product(bool, UseFastJNIAccessors, true, \
789 "Use optimized versions of Get<Primitive>Field") \
790 \
791 product(intx, MaxJNILocalCapacity, 65536, \
792 "Maximum allowable local JNI handle capacity to " \
793 "EnsureLocalCapacity() and PushLocalFrame(), " \
794 "where <= 0 is unlimited, default: 65536") \
795 range(min_intx, max_intx) \
796 \
797 product(bool, EagerXrunInit, false, \
798 "Eagerly initialize -Xrun libraries; allows startup profiling, " \
799 "but not all -Xrun libraries may support the state of the VM " \
800 "at this time") \
801 \
802 develop(uintx, PreallocatedOutOfMemoryErrorCount, 4, \
803 "Number of OutOfMemoryErrors preallocated with backtrace") \
804 range(0, 1024) \
805 \
806 product(bool, PrintFieldLayout, false, DIAGNOSTIC, \
807 "Print field layout for each class") \
808 \
809 product(bool, PrintInlineLayout, false, DIAGNOSTIC, \
810 "Print field layout for each value class or class containing " \
811 "inlined value fields") \
812 \
813 product(bool, PrintFlatArrayLayout, false, DIAGNOSTIC, \
814 "Print array layout for each flattened value array") \
815 \
816 product(bool, UseArrayFlattening, true, DIAGNOSTIC, \
817 "Allow the JVM to flatten arrays of concrete value objects " \
818 "when it determines it is possible and beneficial to do so") \
819 \
820 product(bool, UseFieldFlattening, true, DIAGNOSTIC, \
821 "Allow the JVM to inline the fields of concrete value objects " \
822 "when it determines it is possible and beneficial to do so") \
823 \
824 product(bool, UseNullableAtomicValueFlattening, true, DIAGNOSTIC, \
825 "Allow the JVM to flatten some nullable atomic values") \
826 \
827 product(bool, UseNullFreeNonAtomicValueFlattening, true, EXPERIMENTAL, \
828 "Allow the JVM to flatten some null-free non-atomic values") \
829 \
830 product(bool, UseNullFreeAtomicValueFlattening, true, EXPERIMENTAL, \
831 "Allow the JVM to flatten some null-free atomic values") \
832 \
833 product(bool, UseNullableNonAtomicValueFlattening, true, DIAGNOSTIC, \
834 "Allow the JVM to flatten some strict final non-static fields") \
835 \
836 product(intx, FlatArrayElementMaxOops, 4, DIAGNOSTIC, \
837 "Max number of embedded object references in a value container " \
838 "before no flattening attempts are made, <0 indicates no limit") \
839 \
840 product(uint, FlatteningBudget, 1024, EXPERIMENTAL, \
841 "Maximum size (in bytes) dedicated to flat fields in an instance")\
842 range(0, 1024 * 1024) \
843 develop(ccstrlist, PrintInlineKlassFields, "", \
844 "Print fields collected by InlineKlass::collect_fields") \
845 \
846 /* Need to limit the extent of the padding to reasonable size. */\
847 /* 8K is well beyond the reasonable HW cache line size, even with */\
848 /* aggressive prefetching, while still leaving the room for segregating */\
849 /* among the distinct pages. */\
850 product(int, ContendedPaddingWidth, 128, \
851 "How many bytes to pad the fields/classes marked @Contended with")\
852 range(0, 8192) \
853 constraint(ContendedPaddingWidthConstraintFunc,AfterErgo) \
854 \
855 product(bool, EnableContended, true, \
856 "Enable @Contended annotation support") \
857 \
858 product(bool, RestrictContended, true, \
859 "Restrict @Contended to trusted classes") \
860 \
861 product(int, DiagnoseSyncOnValueBasedClasses, 0, DIAGNOSTIC, \
862 "Detect and take action upon identifying synchronization on " \
863 "value based classes. Modes: " \
864 "0: off; " \
865 "1: exit with fatal error; " \
866 "2: log message to stdout. Output file can be specified with " \
867 " -Xlog:valuebasedclasses. If JFR is running it will " \
868 " also generate JFR events.") \
869 range(0, 2) \
870 \
871 product(bool, ExitOnOutOfMemoryError, false, \
872 "JVM exits on the first occurrence of an out-of-memory error " \
873 "thrown from JVM") \
874 \
875 product(bool, CrashOnOutOfMemoryError, false, \
876 "JVM aborts, producing an error log and core/mini dump, on the " \
877 "first occurrence of an out-of-memory error thrown from JVM") \
878 \
879 product(intx, UserThreadWaitAttemptsAtExit, 30, \
880 "The number of times to wait for user threads to stop executing " \
881 "native code during JVM exit. Each wait lasts 10 milliseconds. " \
882 "The maximum number of waits is 1000, to wait at most 10 " \
883 "seconds.") \
884 range(0, 1000) \
885 \
886 /* tracing */ \
887 \
888 develop(bool, StressRewriter, false, \
889 "Stress linktime bytecode rewriting") \
890 \
891 product(ccstr, TraceJVMTI, nullptr, \
892 "Trace flags for JVMTI functions and events") \
893 \
894 product(bool, StressLdcRewrite, false, DIAGNOSTIC, \
895 "Force ldc -> ldc_w rewrite during RedefineClasses. " \
896 "This option can change an EMCP method into an obsolete method " \
897 "and can affect tests that expect specific methods to be EMCP. " \
898 "This option should be used with caution.") \
899 \
900 product(bool, AllowRedefinitionToAddDeleteMethods, false, \
901 "(Deprecated) Allow redefinition to add and delete private " \
902 "static or final methods for compatibility with old releases") \
903 \
904 develop(bool, TraceBytecodes, false, \
905 "Trace bytecode execution") \
906 \
907 develop(bool, TraceBytecodesTruncated, false, \
908 "Truncate non control-flow bytecode when tracing bytecode") \
909 \
910 develop(bool, VerifyDependencies, trueInDebug, \
911 "Exercise and verify the compilation dependency mechanism") \
912 \
913 develop(bool, TimeOopMap, false, \
914 "Time calls to GenerateOopMap::compute_map() in sum") \
915 \
916 develop(bool, GenerateOopMapALot, false, \
917 "Generate interpreter oopmaps at all safepoints") \
918 \
919 develop(bool, TraceFinalizerRegistration, false, \
920 "Trace registration of final references") \
921 \
922 product(bool, IgnoreEmptyClassPaths, false, \
923 "Ignore empty path elements in -classpath") \
924 \
925 product(bool, PrintHeapAtSIGBREAK, true, \
926 "Print heap layout in response to SIGBREAK") \
927 \
928 product(bool, PrintClassHistogram, false, MANAGEABLE, \
929 "Print a histogram of class instances") \
930 \
931 product(double, ObjectCountCutOffPercent, 0.5, EXPERIMENTAL, \
932 "The percentage of the used heap that the instances of a class " \
933 "must occupy for the class to generate a trace event") \
934 range(0.0, 100.0) \
935 \
936 /* JVMTI heap profiling */ \
937 \
938 product(bool, VerifyBeforeIteration, false, DIAGNOSTIC, \
939 "Verify memory system before JVMTI iteration") \
940 \
941 /* compiler */ \
942 \
943 /* notice: the max range value here is max_jint, not max_intx */ \
944 /* because of overflow issue */ \
945 product(intx, CICompilerCount, CI_COMPILER_COUNT, \
946 "Number of compiler threads to run") \
947 range(0, max_jint) \
948 constraint(CICompilerCountConstraintFunc, AfterErgo) \
949 \
950 product(bool, UseDynamicNumberOfCompilerThreads, true, \
951 "Dynamically choose the number of parallel compiler threads") \
952 \
953 product(bool, ReduceNumberOfCompilerThreads, true, DIAGNOSTIC, \
954 "Reduce the number of parallel compiler threads when they " \
955 "are not used") \
956 \
957 product(bool, TraceCompilerThreads, false, DIAGNOSTIC, \
958 "Trace creation and removal of compiler threads") \
959 \
960 product(ccstr, LogClassLoadingCauseFor, nullptr, \
961 "Apply -Xlog:class+load+cause* to classes whose fully " \
962 "qualified name contains this string (\"*\" matches " \
963 "any class).") \
964 \
965 develop(bool, InjectCompilerCreationFailure, false, \
966 "Inject thread creation failures for " \
967 "UseDynamicNumberOfCompilerThreads") \
968 \
969 product_pd(bool, ImplicitNullChecks, DIAGNOSTIC, \
970 "Generate code for implicit null checks") \
971 \
972 product_pd(bool, TrapBasedNullChecks, \
973 "Generate code for null checks that uses a cmp and trap " \
974 "instruction raising SIGTRAP. This is only used if an access to" \
975 "null (+offset) will not raise a SIGSEGV, i.e.," \
976 "ImplicitNullChecks don't work (PPC64).") \
977 \
978 product(bool, EnableThreadSMRStatistics, trueInDebug, DIAGNOSTIC, \
979 "Enable Thread SMR Statistics") \
980 \
981 product(bool, Inline, true, \
982 "Enable inlining") \
983 \
984 product(bool, ClipInlining, true, \
985 "Clip inlining if aggregate method exceeds DesiredMethodLimit") \
986 \
987 develop(bool, UseCHA, true, \
988 "Enable CHA") \
989 \
990 product(bool, UseTypeProfile, true, \
991 "Check interpreter profile for historically monomorphic calls") \
992 \
993 product(bool, PrintInlining, false, DIAGNOSTIC, \
994 "Print inlining optimizations") \
995 \
996 product(bool, UsePopCountInstruction, false, \
997 "Use population count instruction") \
998 \
999 develop(bool, TraceMethodReplacement, false, \
1000 "Print when methods are replaced do to recompilation") \
1001 \
1002 product(intx, MinPassesBeforeFlush, 10, DIAGNOSTIC, \
1003 "Minimum number of sweeper passes before an nmethod " \
1004 "can be flushed") \
1005 range(0, max_intx) \
1006 \
1007 develop(bool, StressCodeBuffers, false, \
1008 "Exercise code buffer expansion and other rare state changes") \
1009 \
1010 product(bool, DebugNonSafepoints, trueInDebug, DIAGNOSTIC, \
1011 "Generate extra debugging information for non-safepoints in " \
1012 "nmethods") \
1013 \
1014 product(bool, PrintVMOptions, false, \
1015 "Print flags that appeared on the command line") \
1016 \
1017 product(bool, IgnoreUnrecognizedVMOptions, false, \
1018 "Ignore unrecognized VM options") \
1019 \
1020 product(bool, PrintCommandLineFlags, false, \
1021 "Print flags specified on command line or set by ergonomics") \
1022 \
1023 product(bool, PrintFlagsInitial, false, \
1024 "Print all VM flags before argument processing and exit VM") \
1025 \
1026 product(bool, PrintFlagsFinal, false, \
1027 "Print all VM flags after argument and ergonomic processing") \
1028 \
1029 develop(bool, PrintFlagsWithComments, false, \
1030 "Print all VM flags with default values and descriptions and " \
1031 "exit") \
1032 \
1033 product(bool, PrintFlagsRanges, false, \
1034 "Print VM flags and their ranges") \
1035 \
1036 product(bool, SerializeVMOutput, true, DIAGNOSTIC, \
1037 "Use a mutex to serialize output to tty and LogFile") \
1038 \
1039 product(bool, DisplayVMOutput, true, DIAGNOSTIC, \
1040 "Display all VM output on the tty, independently of LogVMOutput") \
1041 \
1042 product(bool, LogVMOutput, false, DIAGNOSTIC, \
1043 "Save VM output to LogFile") \
1044 \
1045 product(ccstr, LogFile, nullptr, DIAGNOSTIC, \
1046 "If LogVMOutput or LogCompilation is on, save VM output to " \
1047 "this file [default: ./hotspot_pid%p.log] (%p replaced with pid)")\
1048 \
1049 product(ccstr, ErrorFile, nullptr, \
1050 "If an error occurs, save the error data to this file " \
1051 "[default: ./hs_err_pid%p.log] (%p replaced with pid)") \
1052 \
1053 product(bool, ExtensiveErrorReports, \
1054 PRODUCT_ONLY(false) NOT_PRODUCT(true), \
1055 "Error reports are more extensive.") \
1056 \
1057 product(bool, DisplayVMOutputToStderr, false, \
1058 "If DisplayVMOutput is true, display all VM output to stderr") \
1059 \
1060 product(bool, DisplayVMOutputToStdout, false, \
1061 "If DisplayVMOutput is true, display all VM output to stdout") \
1062 \
1063 product(bool, ErrorFileToStderr, false, \
1064 "If true, error data is printed to stderr instead of a file") \
1065 \
1066 product(bool, ErrorFileToStdout, false, \
1067 "If true, error data is printed to stdout instead of a file") \
1068 \
1069 product(bool, PrintStringTableStatistics, false, \
1070 "print statistics about the StringTable and SymbolTable") \
1071 \
1072 product(bool, VerifyStringTableAtExit, false, DIAGNOSTIC, \
1073 "verify StringTable contents at exit") \
1074 \
1075 develop(bool, PrintSymbolTableSizeHistogram, false, \
1076 "print histogram of the symbol table") \
1077 \
1078 product(ccstr, AbortVMOnException, nullptr, DIAGNOSTIC, \
1079 "Call fatal if this exception is thrown. Example: " \
1080 "java -XX:AbortVMOnException=java.lang.NullPointerException Foo") \
1081 \
1082 product(ccstr, AbortVMOnExceptionMessage, nullptr, DIAGNOSTIC, \
1083 "Call fatal if the exception pointed by AbortVMOnException " \
1084 "has this message") \
1085 \
1086 develop(bool, DebugVtables, false, \
1087 "add debugging code to vtable dispatch") \
1088 \
1089 product(bool, RangeCheckElimination, true, \
1090 "Eliminate range checks") \
1091 \
1092 develop_pd(bool, UncommonNullCast, \
1093 "track occurrences of null in casts; adjust compiler tactics") \
1094 \
1095 develop(bool, TypeProfileCasts, true, \
1096 "treat casts like calls for purposes of type profiling") \
1097 \
1098 develop(bool, TraceLivenessGen, false, \
1099 "Trace the generation of liveness analysis information") \
1100 \
1101 develop(bool, TraceLivenessQuery, false, \
1102 "Trace queries of liveness analysis information") \
1103 \
1104 develop(bool, CollectIndexSetStatistics, false, \
1105 "Collect information about IndexSets") \
1106 \
1107 /* This value is later shifted left by up to LogBytesPerLong bits */\
1108 /* (to convert from element count to size in bytes), so we must ensure */\
1109 /* it does not overflow during the shift. */\
1110 develop(int, FastAllocateSizeLimit, 128*K, \
1111 /* Note: This value is zero mod 1<<13 for a cheap sparc set. */ \
1112 "Inline allocations larger than this in doublewords must go slow")\
1113 range(0, (1 << (BitsPerInt - LogBytesPerLong - 1)) - 1) \
1114 \
1115 product_pd(bool, CompactStrings, \
1116 "Enable Strings to use single byte chars in backing store") \
1117 \
1118 product_pd(uint, TypeProfileLevel, \
1119 "=XYZ, with Z: Type profiling of arguments at call; " \
1120 "Y: Type profiling of return value at call; " \
1121 "X: Type profiling of parameters to methods; " \
1122 "X, Y and Z in 0=off ; 1=jsr292 only; 2=all methods") \
1123 constraint(TypeProfileLevelConstraintFunc, AfterErgo) \
1124 \
1125 product(int, TypeProfileArgsLimit, 2, \
1126 "max number of call arguments to consider for type profiling") \
1127 range(0, 16) \
1128 \
1129 product(int, TypeProfileParmsLimit, 2, \
1130 "max number of incoming parameters to consider for type profiling"\
1131 ", -1 for all") \
1132 range(-1, 64) \
1133 \
1134 /* statistics */ \
1135 develop(bool, CountCompiledCalls, false, \
1136 "Count method invocations") \
1137 \
1138 develop(bool, ICMissHistogram, false, \
1139 "Produce histogram of IC misses") \
1140 \
1141 /* interpreter */ \
1142 product_pd(bool, RewriteBytecodes, \
1143 "Allow rewriting of bytecodes (bytecodes are not immutable)") \
1144 \
1145 product_pd(bool, RewriteFrequentPairs, \
1146 "Rewrite frequently used bytecode pairs into a single bytecode") \
1147 \
1148 product(bool, PrintInterpreter, false, DIAGNOSTIC, \
1149 "Print the generated interpreter code") \
1150 \
1151 product(bool, UseInterpreter, true, \
1152 "Use interpreter for non-compiled methods") \
1153 \
1154 develop(bool, UseFastSignatureHandlers, true, \
1155 "Use fast signature handlers for native calls") \
1156 \
1157 product(bool, UseLoopCounter, true, \
1158 "Increment invocation counter on backward branch") \
1159 \
1160 product_pd(bool, UseOnStackReplacement, \
1161 "Use on stack replacement, calls runtime if invoc. counter " \
1162 "overflows in loop") \
1163 \
1164 develop(bool, TraceOnStackReplacement, false, \
1165 "Trace on stack replacement") \
1166 \
1167 product_pd(bool, PreferInterpreterNativeStubs, \
1168 "Use always interpreter stubs for native methods invoked via " \
1169 "interpreter") \
1170 \
1171 develop(bool, CountBytecodes, false, \
1172 "Count number of bytecodes executed") \
1173 \
1174 develop(bool, PrintBytecodeHistogram, false, \
1175 "Print histogram of the executed bytecodes") \
1176 \
1177 develop(bool, PrintBytecodePairHistogram, false, \
1178 "Print histogram of the executed bytecode pairs") \
1179 \
1180 product(bool, PrintSignatureHandlers, false, DIAGNOSTIC, \
1181 "Print code generated for native method signature handlers") \
1182 \
1183 develop(bool, VerifyOops, false, \
1184 "Do plausibility checks for oops") \
1185 \
1186 develop(bool, CheckUnhandledOops, false, \
1187 "Check for unhandled oops in VM code") \
1188 \
1189 develop(bool, VerifyJNIFields, trueInDebug, \
1190 "Verify jfieldIDs for instance fields") \
1191 \
1192 develop(bool, VerifyActivationFrameSize, false, \
1193 "Verify that activation frame didn't become smaller than its " \
1194 "minimal size") \
1195 \
1196 develop(bool, TraceFrequencyInlining, false, \
1197 "Trace frequency based inlining") \
1198 \
1199 develop_pd(bool, InlineIntrinsics, \
1200 "Use intrinsics in Interpreter that can be statically resolved") \
1201 \
1202 product_pd(bool, ProfileInterpreter, \
1203 "Profile at the bytecode level during interpretation") \
1204 \
1205 develop_pd(bool, ProfileTraps, \
1206 "Profile deoptimization traps at the bytecode level") \
1207 \
1208 product(intx, ProfileMaturityPercentage, 20, \
1209 "number of method invocations/branches (expressed as % of " \
1210 "CompileThreshold) before using the method's profile") \
1211 range(0, 100) \
1212 \
1213 product(bool, PrintMethodData, false, DIAGNOSTIC, \
1214 "Print the results of +ProfileInterpreter at end of run") \
1215 \
1216 develop(bool, VerifyDataPointer, trueInDebug, \
1217 "Verify the method data pointer during interpreter profiling") \
1218 \
1219 develop(bool, CrashGCForDumpingJavaThread, false, \
1220 "Manually make GC thread crash then dump java stack trace; " \
1221 "Test only") \
1222 \
1223 /* compilation */ \
1224 product(bool, UseCompiler, true, \
1225 "Use Just-In-Time compilation") \
1226 \
1227 product(bool, AlwaysCompileLoopMethods, false, \
1228 "(Deprecated) When using recompilation, never interpret methods " \
1229 "containing loops") \
1230 \
1231 product(int, AllocatePrefetchStyle, 1, \
1232 "0 = no prefetch, " \
1233 "1 = generate prefetch instructions for each allocation, " \
1234 "2 = use TLAB watermark to gate allocation prefetch, " \
1235 "3 = generate one prefetch instruction per cache line") \
1236 range(0, 3) \
1237 \
1238 product(int, AllocatePrefetchDistance, -1, \
1239 "Distance to prefetch ahead of allocation pointer. " \
1240 "-1: use system-specific value (automatically determined") \
1241 range(-1, 512) \
1242 \
1243 product(int, AllocatePrefetchLines, 3, \
1244 "Number of lines to prefetch ahead of array allocation pointer") \
1245 range(1, 64) \
1246 \
1247 product(int, AllocateInstancePrefetchLines, 1, \
1248 "Number of lines to prefetch ahead of instance allocation " \
1249 "pointer") \
1250 range(1, 64) \
1251 \
1252 product(int, AllocatePrefetchStepSize, 16, \
1253 "Step size in bytes of sequential prefetch instructions") \
1254 range(1, 512) \
1255 constraint(AllocatePrefetchStepSizeConstraintFunc,AfterMemoryInit)\
1256 \
1257 product(intx, AllocatePrefetchInstr, 0, \
1258 "Select instruction to prefetch ahead of allocation pointer") \
1259 constraint(AllocatePrefetchInstrConstraintFunc, AfterMemoryInit) \
1260 \
1261 /* deoptimization */ \
1262 product(bool, TraceDeoptimization, false, DIAGNOSTIC, \
1263 "Trace deoptimization") \
1264 \
1265 develop(bool, PrintDeoptimizationDetails, false, \
1266 "Print more information about deoptimization") \
1267 \
1268 develop(bool, DebugDeoptimization, false, \
1269 "Tracing various information while debugging deoptimization") \
1270 \
1271 product(double, SelfDestructTimer, 0.0, \
1272 "Will cause VM to terminate after a given time " \
1273 "(in fractional minutes) " \
1274 "(0.0 means off)") \
1275 range(0.0, (double)max_intx) \
1276 \
1277 product(int, MaxJavaStackTraceDepth, 1024, \
1278 "The maximum number of lines in the stack trace for Java " \
1279 "exceptions (0 means all)") \
1280 range(0, max_jint/2) \
1281 \
1282 /* notice: the max range value here is max_jint, not max_intx */ \
1283 /* because of overflow issue */ \
1284 product(intx, GuaranteedSafepointInterval, 0, DIAGNOSTIC, \
1285 "Guarantee a safepoint (at least) every so many milliseconds " \
1286 "(0 means none)") \
1287 range(0, max_jint) \
1288 \
1289 product(intx, ServiceThreadCleanupInterval, 1000, DIAGNOSTIC, \
1290 "Wake the ServiceThread to do periodic cleanup checks every so " \
1291 "many milliseconds (0 means none)") \
1292 range(0, max_jint) \
1293 \
1294 product(double, SafepointTimeoutDelay, 10000, \
1295 "Delay in milliseconds for option SafepointTimeout; " \
1296 "supports sub-millisecond resolution with fractional values.") \
1297 range(0, max_jlongDouble LP64_ONLY(/MICROUNITS)) \
1298 \
1299 product(bool, UseSystemMemoryBarrier, false, \
1300 "Try to enable system memory barrier if supported by OS") \
1301 \
1302 product(intx, NmethodSweepActivity, 4, \
1303 "Removes cold nmethods from code cache if > 0. Higher values " \
1304 "result in more aggressive sweeping") \
1305 range(0, 2000) \
1306 \
1307 develop(intx, MallocCatchPtr, -1, \
1308 "Hit breakpoint when mallocing/freeing this pointer") \
1309 \
1310 develop(int, StackPrintLimit, 100, \
1311 "number of stack frames to print in VM-level stack dump") \
1312 \
1313 product(int, ErrorLogPrintCodeLimit, 3, DIAGNOSTIC, \
1314 "max number of compiled code units to print in error log") \
1315 range(0, VMError::max_error_log_print_code) \
1316 \
1317 develop(int, MaxElementPrintSize, 256, \
1318 "maximum number of elements to print") \
1319 \
1320 develop(int, MaxStringPrintSize, 256, \
1321 "maximum number of characters to print for a java.lang.String " \
1322 "in the VM. If exceeded, an abridged version of the string is " \
1323 "printed with the middle of the string elided.") \
1324 range(2, O_BUFLEN) \
1325 \
1326 develop(intx, MaxSubklassPrintSize, 4, \
1327 "maximum number of subklasses to print when printing klass") \
1328 \
1329 develop(intx, MaxForceInlineLevel, 100, \
1330 "maximum number of nested calls that are forced for inlining " \
1331 "(using CompileCommand or marked w/ @ForceInline)") \
1332 range(0, max_jint) \
1333 \
1334 develop(intx, MethodHistogramCutoff, 100, \
1335 "The cutoff value for method invocation histogram (+CountCalls)") \
1336 \
1337 develop(intx, DeoptimizeALotInterval, 5, \
1338 "Number of exits until DeoptimizeALot kicks in") \
1339 \
1340 develop(intx, ZombieALotInterval, 5, \
1341 "Number of exits until ZombieALot kicks in") \
1342 \
1343 product(ccstr, MallocLimit, nullptr, DIAGNOSTIC, \
1344 "Limit malloc allocation size from VM. Reaching a limit will " \
1345 "trigger an action (see flag). This feature requires " \
1346 "NativeMemoryTracking=summary or NativeMemoryTracking=detail." \
1347 "Usage:" \
1348 "\"-XX:MallocLimit=<size>[:<flag>]\" sets a total limit." \
1349 "\"-XX:MallocLimit=<category>:<size>[:<flag>][,<category>:<size>[:<flag>] ...]\"" \
1350 "sets one or more category-specific limits." \
1351 "<flag> defines the action upon reaching the limit:" \
1352 "\"fatal\": end VM with a fatal error at the allocation site" \
1353 "\"oom\" : will mimic a native OOM" \
1354 "If <flag> is omitted, \"fatal\" is the default." \
1355 "Examples:\n" \
1356 "-XX:MallocLimit=2g" \
1357 "-XX:MallocLimit=2g:oom" \
1358 "-XX:MallocLimit=compiler:200m:oom,code:100m") \
1359 \
1360 product(intx, TypeProfileWidth, 2, \
1361 "Number of receiver types to record in call/cast profile") \
1362 range(0, 8) \
1363 \
1364 develop(intx, BciProfileWidth, 2, \
1365 "Number of return bci's to record in ret profile") \
1366 \
1367 product(intx, PerMethodRecompilationCutoff, 400, \
1368 "After recompiling N times, stay in the interpreter (-1=>'Inf')") \
1369 range(-1, max_intx) \
1370 \
1371 product(intx, PerBytecodeRecompilationCutoff, 200, \
1372 "Per-BCI limit on repeated recompilation (-1=>'Inf')") \
1373 range(-1, max_intx) \
1374 \
1375 product(intx, PerMethodTrapLimit, 100, \
1376 "Limit on traps (of one kind) in a method (includes inlines)") \
1377 range(0, max_jint) \
1378 \
1379 product(intx, PerMethodSpecTrapLimit, 5000, EXPERIMENTAL, \
1380 "Limit on speculative traps (of one kind) in a method " \
1381 "(includes inlines)") \
1382 range(0, max_jint) \
1383 \
1384 product(intx, PerBytecodeTrapLimit, 4, \
1385 "Limit on traps (of one kind) at a particular BCI") \
1386 range(0, max_jint) \
1387 \
1388 product(int, SpecTrapLimitExtraEntries, 3, EXPERIMENTAL, \
1389 "Extra method data trap entries for speculation") \
1390 range(0, 100) \
1391 \
1392 product(double, InlineFrequencyRatio, 0.25, DIAGNOSTIC, \
1393 "Ratio of call site execution to caller method invocation") \
1394 \
1395 product(double, MinInlineFrequencyRatio, 0.0085, DIAGNOSTIC, \
1396 "Minimum ratio of call site execution to caller method" \
1397 "invocation to be considered for inlining") \
1398 \
1399 develop(intx, InlineThrowCount, 50, \
1400 "Force inlining of interpreted methods that throw this often") \
1401 range(0, max_jint) \
1402 \
1403 develop(intx, InlineThrowMaxSize, 200, \
1404 "Force inlining of throwing methods smaller than this") \
1405 range(0, max_jint) \
1406 \
1407 product(size_t, MetaspaceSize, NOT_LP64(16 * M) LP64_ONLY(21 * M), \
1408 "Initial threshold (in bytes) at which a garbage collection " \
1409 "is done to reduce Metaspace usage") \
1410 constraint(MetaspaceSizeConstraintFunc,AfterErgo) \
1411 \
1412 product(size_t, MaxMetaspaceSize, max_uintx, \
1413 "Maximum size of Metaspaces (in bytes)") \
1414 constraint(MaxMetaspaceSizeConstraintFunc,AfterErgo) \
1415 \
1416 product(size_t, CompressedClassSpaceSize, 1*G, \
1417 "Maximum size of class area in Metaspace when compressed " \
1418 "class pointers are used") \
1419 range(1*M, LP64_ONLY(4*G) NOT_LP64(max_uintx)) \
1420 \
1421 develop(size_t, CompressedClassSpaceBaseAddress, 0, \
1422 "Force the class space to be allocated at this address or " \
1423 "fails VM initialization (requires -Xshare=off.") \
1424 \
1425 develop(bool, RandomizeClassSpaceLocation, true, \
1426 "Randomize location of class space.") \
1427 \
1428 product(bool, PrintMetaspaceStatisticsAtExit, false, DIAGNOSTIC, \
1429 "Print metaspace statistics upon VM exit.") \
1430 \
1431 product(bool, PrintCompilerMemoryStatisticsAtExit, false, DIAGNOSTIC, \
1432 "Print compiler memory statistics upon VM exit.") \
1433 \
1434 product(uintx, MinHeapFreeRatio, 40, MANAGEABLE, \
1435 "The minimum percentage of heap free after GC to avoid expansion."\
1436 " For most GCs this applies to the old generation. In G1 and" \
1437 " ParallelGC it applies to the whole heap.") \
1438 range(0, 100) \
1439 constraint(MinHeapFreeRatioConstraintFunc,AfterErgo) \
1440 \
1441 product(uintx, MaxHeapFreeRatio, 70, MANAGEABLE, \
1442 "The maximum percentage of heap free after GC to avoid shrinking."\
1443 " For most GCs this applies to the old generation. In G1 and" \
1444 " ParallelGC it applies to the whole heap.") \
1445 range(0, 100) \
1446 constraint(MaxHeapFreeRatioConstraintFunc,AfterErgo) \
1447 \
1448 product(intx, SoftRefLRUPolicyMSPerMB, 1000, \
1449 "Number of milliseconds per MB of free space in the heap") \
1450 range(0, max_intx) \
1451 constraint(SoftRefLRUPolicyMSPerMBConstraintFunc,AfterMemoryInit) \
1452 \
1453 product(size_t, MinHeapDeltaBytes, ScaleForWordSize(128*K), \
1454 "The minimum change in heap space due to GC (in bytes)") \
1455 range(0, max_uintx / 2 + 1) \
1456 \
1457 product(size_t, MinMetaspaceExpansion, ScaleForWordSize(256*K), \
1458 "The minimum expansion of Metaspace (in bytes)") \
1459 range(0, max_uintx) \
1460 \
1461 product(uint, MaxMetaspaceFreeRatio, 70, \
1462 "The maximum percentage of Metaspace free after GC to avoid " \
1463 "shrinking") \
1464 range(0, 100) \
1465 constraint(MaxMetaspaceFreeRatioConstraintFunc,AfterErgo) \
1466 \
1467 product(uint, MinMetaspaceFreeRatio, 40, \
1468 "The minimum percentage of Metaspace free after GC to avoid " \
1469 "expansion") \
1470 range(0, 99) \
1471 constraint(MinMetaspaceFreeRatioConstraintFunc,AfterErgo) \
1472 \
1473 product(size_t, MaxMetaspaceExpansion, ScaleForWordSize(4*M), \
1474 "The maximum expansion of Metaspace without full GC (in bytes)") \
1475 range(0, max_uintx) \
1476 \
1477 /* stack parameters */ \
1478 product_pd(intx, StackYellowPages, \
1479 "Number of yellow zone (recoverable overflows) pages of size " \
1480 "4KB. If pages are bigger yellow zone is aligned up.") \
1481 range(MIN_STACK_YELLOW_PAGES, (DEFAULT_STACK_YELLOW_PAGES+5)) \
1482 \
1483 product_pd(intx, StackRedPages, \
1484 "Number of red zone (unrecoverable overflows) pages of size " \
1485 "4KB. If pages are bigger red zone is aligned up.") \
1486 range(MIN_STACK_RED_PAGES, (DEFAULT_STACK_RED_PAGES+2)) \
1487 \
1488 product_pd(intx, StackReservedPages, \
1489 "Number of reserved zone (reserved to annotated methods) pages" \
1490 " of size 4KB. If pages are bigger reserved zone is aligned up.") \
1491 range(MIN_STACK_RESERVED_PAGES, (DEFAULT_STACK_RESERVED_PAGES+10))\
1492 \
1493 product(bool, RestrictReservedStack, true, \
1494 "Restrict @ReservedStackAccess to trusted classes") \
1495 \
1496 /* greater stack shadow pages can't generate instruction to bang stack */ \
1497 product_pd(intx, StackShadowPages, \
1498 "Number of shadow zone (for overflow checking) pages of size " \
1499 "4KB. If pages are bigger shadow zone is aligned up. " \
1500 "This should exceed the depth of the VM and native call stack.") \
1501 range(MIN_STACK_SHADOW_PAGES, (DEFAULT_STACK_SHADOW_PAGES+30)) \
1502 \
1503 product_pd(intx, ThreadStackSize, \
1504 "Thread Stack Size (in Kbytes)") \
1505 range(0, 1 * M) \
1506 \
1507 product_pd(intx, VMThreadStackSize, \
1508 "Non-Java Thread Stack Size (in Kbytes)") \
1509 range(0, max_intx/(1 * K)) \
1510 \
1511 product_pd(intx, CompilerThreadStackSize, \
1512 "Compiler Thread Stack Size (in Kbytes)") \
1513 range(0, max_intx/(1 * K)) \
1514 \
1515 develop_pd(size_t, JVMInvokeMethodSlack, \
1516 "Stack space (bytes) required for JVM_InvokeMethod to complete") \
1517 \
1518 /* code cache parameters */ \
1519 product_pd(size_t, CodeCacheSegmentSize, EXPERIMENTAL, \
1520 "Code cache segment size (in bytes) - smallest unit of " \
1521 "allocation") \
1522 range(1, 1024) \
1523 constraint(CodeCacheSegmentSizeConstraintFunc, AfterErgo) \
1524 \
1525 product_pd(uint, CodeEntryAlignment, EXPERIMENTAL, \
1526 "Code entry alignment for generated code" \
1527 " (in bytes, power of two)") \
1528 constraint(CodeEntryAlignmentConstraintFunc, AfterErgo) \
1529 \
1530 product_pd(intx, OptoLoopAlignment, \
1531 "Align inner loops to zero relative to this modulus") \
1532 range(1, 128) \
1533 constraint(OptoLoopAlignmentConstraintFunc, AfterErgo) \
1534 \
1535 product_pd(size_t, InitialCodeCacheSize, \
1536 "Initial code cache size (in bytes)") \
1537 constraint(VMPageSizeConstraintFunc, AtParse) \
1538 \
1539 develop_pd(size_t, CodeCacheMinimumUseSpace, \
1540 "Minimum code cache size (in bytes) required to start VM.") \
1541 range(0, SIZE_MAX) \
1542 \
1543 product(bool, SegmentedCodeCache, false, \
1544 "Use a segmented code cache") \
1545 \
1546 product_pd(size_t, ReservedCodeCacheSize, \
1547 "Reserved code cache size (in bytes) - maximum code cache size") \
1548 constraint(VMPageSizeConstraintFunc, AtParse) \
1549 \
1550 product_pd(size_t, NonProfiledCodeHeapSize, \
1551 "Size of code heap with non-profiled methods (in bytes)") \
1552 range(0, SIZE_MAX) \
1553 \
1554 product_pd(size_t, ProfiledCodeHeapSize, \
1555 "Size of code heap with profiled methods (in bytes)") \
1556 range(0, SIZE_MAX) \
1557 \
1558 product_pd(size_t, NonNMethodCodeHeapSize, \
1559 "Size of code heap with non-nmethods (in bytes)") \
1560 constraint(VMPageSizeConstraintFunc, AtParse) \
1561 \
1562 product(size_t, HotCodeHeapSize, 0, EXPERIMENTAL, \
1563 "Size of code heap with predicted hot methods (in bytes)") \
1564 range(0, SIZE_MAX) \
1565 \
1566 product_pd(size_t, CodeCacheExpansionSize, \
1567 "Code cache expansion size (in bytes)") \
1568 range(32*K, SIZE_MAX) \
1569 \
1570 product_pd(size_t, CodeCacheMinBlockLength, DIAGNOSTIC, \
1571 "Minimum number of segments in a code cache block") \
1572 range(1, 100) \
1573 \
1574 develop(bool, ExitOnFullCodeCache, false, \
1575 "Exit the VM if we fill the code cache") \
1576 \
1577 product(bool, UseCodeCacheFlushing, true, \
1578 "Remove cold/old nmethods from the code cache") \
1579 \
1580 product(double, SweeperThreshold, 15.0, \
1581 "Threshold when a code cache unloading GC is invoked." \
1582 "Value is percentage of ReservedCodeCacheSize.") \
1583 range(0.0, 100.0) \
1584 \
1585 product(uintx, StartAggressiveSweepingAt, 10, \
1586 "Start aggressive sweeping if less than X[%] of the total code cache is free.")\
1587 range(0, 100) \
1588 \
1589 product(bool, NMethodRelocation, false, EXPERIMENTAL, \
1590 "Enables use of experimental function nmethod::relocate()") \
1591 \
1592 /* interpreter debugging */ \
1593 develop(intx, BinarySwitchThreshold, 5, \
1594 "Minimal number of lookupswitch entries for rewriting to binary " \
1595 "switch") \
1596 \
1597 develop(uintx, StopInterpreterAt, 0, \
1598 "Stop interpreter execution at specified bytecode number") \
1599 \
1600 develop(uintx, TraceBytecodesAt, 0, \
1601 "Trace bytecodes starting with specified bytecode number") \
1602 \
1603 develop(uintx, TraceBytecodesStopAt, 0, \
1604 "Stop bytecode tracing at the specified bytecode number") \
1605 \
1606 /* Priorities */ \
1607 product_pd(bool, UseThreadPriorities, "Use native thread priorities") \
1608 \
1609 product(int, ThreadPriorityPolicy, 0, \
1610 "0 : Normal. "\
1611 " VM chooses priorities that are appropriate for normal "\
1612 " applications. "\
1613 " On Windows applications are allowed to use higher native "\
1614 " priorities. However, with ThreadPriorityPolicy=0, VM will "\
1615 " not use the highest possible native priority, "\
1616 " THREAD_PRIORITY_TIME_CRITICAL, as it may interfere with "\
1617 " system threads. On Linux thread priorities are ignored "\
1618 " because the OS does not support static priority in "\
1619 " SCHED_OTHER scheduling class which is the only choice for "\
1620 " non-root, non-realtime applications. "\
1621 "1 : Aggressive. "\
1622 " Java thread priorities map over to the entire range of "\
1623 " native thread priorities. Higher Java thread priorities map "\
1624 " to higher native thread priorities. This policy should be "\
1625 " used with care, as sometimes it can cause performance "\
1626 " degradation in the application and/or the entire system. On "\
1627 " Linux/BSD/macOS this policy requires root privilege or an "\
1628 " extended capability.") \
1629 range(0, 1) \
1630 \
1631 product(bool, ThreadPriorityVerbose, false, \
1632 "Print priority changes") \
1633 \
1634 product(int, CompilerThreadPriority, -1, \
1635 "The native priority at which compiler threads should run " \
1636 "(-1 means no change)") \
1637 range(min_jint, max_jint) \
1638 \
1639 product(int, VMThreadPriority, -1, \
1640 "The native priority at which the VM thread should run " \
1641 "(-1 means no change)") \
1642 range(min_jint, max_jint) \
1643 \
1644 product(int, JavaPriority1_To_OSPriority, -1, \
1645 "Map Java priorities to OS priorities") \
1646 range(min_jint, max_jint) \
1647 \
1648 product(int, JavaPriority2_To_OSPriority, -1, \
1649 "Map Java priorities to OS priorities") \
1650 range(min_jint, max_jint) \
1651 \
1652 product(int, JavaPriority3_To_OSPriority, -1, \
1653 "Map Java priorities to OS priorities") \
1654 range(min_jint, max_jint) \
1655 \
1656 product(int, JavaPriority4_To_OSPriority, -1, \
1657 "Map Java priorities to OS priorities") \
1658 range(min_jint, max_jint) \
1659 \
1660 product(int, JavaPriority5_To_OSPriority, -1, \
1661 "Map Java priorities to OS priorities") \
1662 range(min_jint, max_jint) \
1663 \
1664 product(int, JavaPriority6_To_OSPriority, -1, \
1665 "Map Java priorities to OS priorities") \
1666 range(min_jint, max_jint) \
1667 \
1668 product(int, JavaPriority7_To_OSPriority, -1, \
1669 "Map Java priorities to OS priorities") \
1670 range(min_jint, max_jint) \
1671 \
1672 product(int, JavaPriority8_To_OSPriority, -1, \
1673 "Map Java priorities to OS priorities") \
1674 range(min_jint, max_jint) \
1675 \
1676 product(int, JavaPriority9_To_OSPriority, -1, \
1677 "Map Java priorities to OS priorities") \
1678 range(min_jint, max_jint) \
1679 \
1680 product(int, JavaPriority10_To_OSPriority,-1, \
1681 "Map Java priorities to OS priorities") \
1682 range(min_jint, max_jint) \
1683 \
1684 product(bool, UseCriticalJavaThreadPriority, false, EXPERIMENTAL, \
1685 "Java thread priority 10 maps to critical scheduling priority") \
1686 \
1687 product(bool, UseCriticalCompilerThreadPriority, false, EXPERIMENTAL, \
1688 "Compiler thread(s) run at critical scheduling priority") \
1689 \
1690 develop(intx, NewCodeParameter, 0, \
1691 "Testing Only: Create a dedicated integer parameter before " \
1692 "putback") \
1693 \
1694 /* new oopmap storage allocation */ \
1695 develop(int, MinOopMapAllocation, 8, \
1696 "Minimum number of OopMap entries in an OopMapSet") \
1697 range(0, max_jint) \
1698 \
1699 /* recompilation */ \
1700 product_pd(intx, CompileThreshold, \
1701 "number of interpreted method invocations before (re-)compiling") \
1702 constraint(CompileThresholdConstraintFunc, AfterErgo) \
1703 \
1704 product_pd(bool, TieredCompilation, \
1705 "Enable tiered compilation") \
1706 \
1707 /* Properties for Java libraries */ \
1708 \
1709 product(uint64_t, MaxDirectMemorySize, 0, \
1710 "Maximum total size of NIO direct-buffer allocations. " \
1711 "Ignored if not explicitly set.") \
1712 range(0, max_jlong) \
1713 \
1714 /* Flags used for temporary code during development */ \
1715 \
1716 product(bool, UseNewCode, false, DIAGNOSTIC, \
1717 "Testing Only: Use the new version while testing") \
1718 \
1719 product(bool, UseNewCode2, false, DIAGNOSTIC, \
1720 "Testing Only: Use the new version while testing") \
1721 \
1722 product(bool, UseNewCode3, false, DIAGNOSTIC, \
1723 "Testing Only: Use the new version while testing") \
1724 \
1725 develop(bool, UseDebuggerErgo, false, \
1726 "Debugging Only: Adjust the VM to be more debugger-friendly. " \
1727 "Turns on the other UseDebuggerErgo* flags") \
1728 \
1729 develop(bool, UseDebuggerErgo1, false, \
1730 "Debugging Only: Enable workarounds for debugger induced " \
1731 "os::processor_id() >= os::processor_count() problems") \
1732 \
1733 develop(bool, UseDebuggerErgo2, false, \
1734 "Debugging Only: Limit the number of spawned JVM threads") \
1735 \
1736 develop(bool, EnableJVMTIStackDepthAsserts, true, \
1737 "Enable JVMTI asserts related to stack depth checks") \
1738 \
1739 /* flags for performance data collection */ \
1740 \
1741 product(bool, UsePerfData, true, \
1742 "Flag to disable jvmstat instrumentation for performance testing "\
1743 "and problem isolation purposes") \
1744 \
1745 product(bool, PerfDataSaveToFile, false, \
1746 "Save PerfData memory to hsperfdata_<pid> file on exit") \
1747 \
1748 product(ccstr, PerfDataSaveFile, nullptr, \
1749 "Save PerfData memory to the specified absolute pathname. " \
1750 "The string %p in the file name (if present) " \
1751 "will be replaced by pid") \
1752 \
1753 product(bool, PerfDisableSharedMem, false, \
1754 "Store performance data in standard memory") \
1755 \
1756 product(int, PerfDataMemorySize, 32*K, \
1757 "Size of performance data memory region. Will be rounded " \
1758 "up to a multiple of the native os page size.") \
1759 range(128, 32*64*K) \
1760 \
1761 product(int, PerfMaxStringConstLength, 1024, \
1762 "Maximum PerfStringConstant string length before truncation") \
1763 range(32, 32*K) \
1764 \
1765 product(bool, PerfAllowAtExitRegistration, false, \
1766 "Allow registration of atexit() methods") \
1767 \
1768 product(bool, PerfBypassFileSystemCheck, false, \
1769 "Bypass Win32 file system criteria checks (Windows Only)") \
1770 \
1771 product(int, UnguardOnExecutionViolation, 0, \
1772 "Unguard page and retry on no-execute fault (Win32 only) " \
1773 "0=off, 1=conservative, 2=aggressive") \
1774 range(0, 2) \
1775 \
1776 /* Serviceability Support */ \
1777 \
1778 product(bool, ManagementServer, false, \
1779 "Create JMX Management Server") \
1780 \
1781 product(bool, DisableAttachMechanism, false, \
1782 "Disable mechanism that allows tools to attach to this VM") \
1783 \
1784 product(bool, StartAttachListener, false, \
1785 "Always start Attach Listener at VM startup") \
1786 \
1787 product(bool, EnableDynamicAgentLoading, true, \
1788 "Allow tools to load agents with the attach mechanism") \
1789 \
1790 product(bool, PrintConcurrentLocks, false, MANAGEABLE, \
1791 "Print java.util.concurrent locks in thread dump") \
1792 \
1793 product(bool, PrintMethodHandleStubs, false, DIAGNOSTIC, \
1794 "Print generated stub code for method handles") \
1795 \
1796 product(bool, VerifyMethodHandles, trueInDebug, DIAGNOSTIC, \
1797 "perform extra checks when constructing method handles") \
1798 \
1799 product(bool, IgnoreAssertUnsetFields, false, DIAGNOSTIC, \
1800 "Ignore assert_unset_fields") \
1801 \
1802 product(bool, ShowHiddenFrames, false, DIAGNOSTIC, \
1803 "show method handle implementation frames (usually hidden)") \
1804 \
1805 product(bool, ShowCarrierFrames, false, DIAGNOSTIC, \
1806 "show virtual threads' carrier frames in exceptions") \
1807 \
1808 product(bool, TrustFinalNonStaticFields, false, EXPERIMENTAL, \
1809 "trust final non-static declarations for constant folding") \
1810 \
1811 product(bool, FoldStableValues, true, DIAGNOSTIC, \
1812 "Optimize loads from stable fields (marked w/ @Stable)") \
1813 \
1814 product(int, UseBootstrapCallInfo, 1, DIAGNOSTIC, \
1815 "0: when resolving InDy or ConDy, force all BSM arguments to be " \
1816 "resolved before the bootstrap method is called; 1: when a BSM " \
1817 "that may accept a BootstrapCallInfo is detected, use that API " \
1818 "to pass BSM arguments, which allows the BSM to delay their " \
1819 "resolution; 2+: stress test the BCI API by calling more BSMs " \
1820 "via that API, instead of with the eagerly-resolved array.") \
1821 \
1822 product(bool, PauseAtStartup, false, DIAGNOSTIC, \
1823 "Causes the VM to pause at startup time and wait for the pause " \
1824 "file to be removed (default: ./vm.paused.<pid>)") \
1825 \
1826 product(ccstr, PauseAtStartupFile, nullptr, DIAGNOSTIC, \
1827 "The file to create and for whose removal to await when pausing " \
1828 "at startup. (default: ./vm.paused.<pid>)") \
1829 \
1830 product(bool, PauseAtExit, false, DIAGNOSTIC, \
1831 "Pause and wait for keypress on exit if a debugger is attached") \
1832 \
1833 product(bool, DTraceMethodProbes, false, \
1834 "Enable dtrace tool probes for method-entry and method-exit") \
1835 \
1836 product(bool, DTraceAllocProbes, false, \
1837 "Enable dtrace tool probes for object allocation") \
1838 \
1839 product(bool, DTraceMonitorProbes, false, \
1840 "Enable dtrace tool probes for monitor events") \
1841 \
1842 product(bool, RelaxAccessControlCheck, false, \
1843 "Relax the access control checks in the verifier") \
1844 \
1845 product(uintx, StringTableSize, defaultStringTableSize, \
1846 "Number of buckets in the interned String table " \
1847 "(will be rounded to nearest higher power of 2)") \
1848 range(minimumStringTableSize, 16777216ul /* 2^24 */) \
1849 \
1850 product(uintx, SymbolTableSize, defaultSymbolTableSize, EXPERIMENTAL, \
1851 "Number of buckets in the JVM internal Symbol table") \
1852 range(minimumSymbolTableSize, 16777216ul /* 2^24 */) \
1853 \
1854 product(bool, UseStringDeduplication, false, \
1855 "Use string deduplication") \
1856 \
1857 product(uint, StringDeduplicationAgeThreshold, 3, \
1858 "A string must reach this age (or be promoted to an old region) " \
1859 "to be considered for deduplication") \
1860 range(1, markWord::max_age) \
1861 \
1862 product(size_t, StringDeduplicationInitialTableSize, 500, EXPERIMENTAL, \
1863 "Approximate initial number of buckets in the table") \
1864 range(1, 1 * G) \
1865 \
1866 product(double, StringDeduplicationGrowTableLoad, 14.0, EXPERIMENTAL, \
1867 "Entries per bucket above which the table should be expanded") \
1868 range(0.1, 1000.0) \
1869 \
1870 product(double, StringDeduplicationShrinkTableLoad, 1.0, EXPERIMENTAL, \
1871 "Entries per bucket below which the table should be shrunk") \
1872 range(0.01, 100.0) \
1873 \
1874 product(double, StringDeduplicationTargetTableLoad, 7.0, EXPERIMENTAL, \
1875 "Desired entries per bucket when resizing the table") \
1876 range(0.01, 1000.0) \
1877 \
1878 product(size_t, StringDeduplicationCleanupDeadMinimum, 100, EXPERIMENTAL, \
1879 "Minimum number of dead table entries for cleaning the table") \
1880 \
1881 product(int, StringDeduplicationCleanupDeadPercent, 5, EXPERIMENTAL, \
1882 "Minimum percentage of dead table entries for cleaning the table") \
1883 range(1, 100) \
1884 \
1885 product(bool, StringDeduplicationResizeALot, false, DIAGNOSTIC, \
1886 "Force more frequent table resizing") \
1887 \
1888 product(uint64_t, StringDeduplicationHashSeed, 0, DIAGNOSTIC, \
1889 "Seed for the table hashing function; 0 requests computed seed") \
1890 \
1891 product(bool, WhiteBoxAPI, false, DIAGNOSTIC, \
1892 "Enable internal testing APIs") \
1893 \
1894 product(bool, UseUnalignedAccesses, false, DIAGNOSTIC, \
1895 "Use unaligned memory accesses in Unsafe") \
1896 \
1897 product_pd(bool, PreserveFramePointer, \
1898 "Use the FP register for holding the frame pointer " \
1899 "and not as a general purpose register.") \
1900 \
1901 product(size_t, AsyncLogBufferSize, 2*M, \
1902 "Memory budget (in bytes) for the buffer of Asynchronous " \
1903 "Logging (-Xlog:async).") \
1904 range(DEBUG_ONLY(192) NOT_DEBUG(100*K), 50*M) \
1905 \
1906 product(bool, CheckIntrinsics, true, DIAGNOSTIC, \
1907 "When a class C is loaded, check that " \
1908 "(1) all intrinsics defined by the VM for class C are present "\
1909 "in the loaded class file and are marked with the " \
1910 "@IntrinsicCandidate annotation, that " \
1911 "(2) there is an intrinsic registered for all loaded methods " \
1912 "that are annotated with the @IntrinsicCandidate annotation, " \
1913 "and that " \
1914 "(3) no orphan methods exist for class C (i.e., methods for " \
1915 "which the VM declares an intrinsic but that are not declared "\
1916 "in the loaded class C. " \
1917 "Check (3) is available only in debug builds.") \
1918 \
1919 product_pd(intx, InitArrayShortSize, DIAGNOSTIC, \
1920 "Threshold small size (in bytes) for clearing arrays. " \
1921 "Anything this size or smaller may get converted to discrete " \
1922 "scalar stores.") \
1923 range(0, max_intx) \
1924 constraint(InitArrayShortSizeConstraintFunc, AfterErgo) \
1925 \
1926 product(ccstr, AllocateHeapAt, nullptr, \
1927 "Path to the directory where a temporary file will be created " \
1928 "to use as the backing store for Java Heap.") \
1929 \
1930 product_pd(bool, VMContinuations, EXPERIMENTAL, \
1931 "Enable VM continuations support") \
1932 \
1933 develop(bool, LoomDeoptAfterThaw, false, \
1934 "Deopt stack after thaw") \
1935 \
1936 develop(bool, LoomVerifyAfterThaw, false, \
1937 "Verify stack after thaw") \
1938 \
1939 develop(bool, VerifyContinuations, false, \
1940 "Verify continuation consistency") \
1941 \
1942 develop(bool, UseContinuationFastPath, true, \
1943 "Use fast-path frame walking in continuations") \
1944 \
1945 develop(bool, ForceSingleFrameThaw, false, \
1946 "Force thawing one frame at a time") \
1947 \
1948 develop(int, VerifyMetaspaceInterval, DEBUG_ONLY(500) NOT_DEBUG(0), \
1949 "Run periodic metaspace verifications (0 - none, " \
1950 "1 - always, >1 every nth interval)") \
1951 \
1952 product(bool, ShowRegistersOnAssert, true, DIAGNOSTIC, \
1953 "On internal errors, include registers in error report.") \
1954 \
1955 product(bool, UseSwitchProfiling, true, DIAGNOSTIC, \
1956 "leverage profiling for table/lookup switch") \
1957 \
1958 develop(bool, TraceMemoryWriteback, false, \
1959 "Trace memory writeback operations") \
1960 \
1961 JFR_ONLY(product(bool, FlightRecorder, false, \
1962 "(Deprecated) Enable Flight Recorder")) \
1963 \
1964 JFR_ONLY(product(ccstr, FlightRecorderOptions, nullptr, \
1965 "Flight Recorder options")) \
1966 \
1967 JFR_ONLY(product(ccstr, StartFlightRecording, nullptr, \
1968 "Start flight recording with options")) \
1969 \
1970 product(bool, UseFastUnorderedTimeStamps, false, EXPERIMENTAL, \
1971 "Use platform unstable time where supported for timestamps only") \
1972 \
1973 product_pd(bool, InlineTypePassFieldsAsArgs, DIAGNOSTIC, \
1974 "Pass each inline type field as an argument at calls") \
1975 \
1976 product_pd(bool, InlineTypeReturnedAsFields, DIAGNOSTIC, \
1977 "Return fields instead of an inline type reference") \
1978 \
1979 develop(bool, StressCallingConvention, false, \
1980 "Stress the scalarized calling convention.") \
1981 \
1982 develop(bool, PreloadClasses, true, \
1983 "Preloading all classes from the LoadableDescriptors attribute") \
1984 \
1985 product(ccstrlist, ForceNonTearable, "", DIAGNOSTIC, \
1986 "List of inline classes which are forced to be atomic " \
1987 "(whitespace and commas separate names, " \
1988 "and leading and trailing stars '*' are wildcards)") \
1989 \
1990 product(bool, DeoptimizeNMethodBarriersALot, false, DIAGNOSTIC, \
1991 "Make nmethod barriers deoptimise a lot.") \
1992 \
1993 develop(bool, VerifyCrossModifyFence, \
1994 false AARCH64_ONLY(DEBUG_ONLY(||true)), \
1995 "Mark all threads after a safepoint, and clear on a modify " \
1996 "fence. Add cleanliness checks.") \
1997 \
1998 product(bool, UseObjectMonitorTable, true, DIAGNOSTIC, \
1999 "Use a table to record inflated monitors rather than the first " \
2000 "word of the object.") \
2001 \
2002 product(int, FastLockingSpins, 8, DIAGNOSTIC, \
2003 "Specifies the number of times fast locking will attempt to " \
2004 "CAS the markWord before inflating. Between each CAS it will " \
2005 "spin for exponentially more time, resulting in a total number " \
2006 "of spins on the order of O(2^value)") \
2007 range(1, 30) \
2008 \
2009 product(uint, TrimNativeHeapInterval, 0, \
2010 "Interval, in ms, at which the JVM will trim the native heap if " \
2011 "the platform supports that. Lower values will reclaim memory " \
2012 "more eagerly at the cost of higher overhead. A value of 0 " \
2013 "(default) disables native heap trimming.") \
2014 range(0, UINT_MAX) \
2015 \
2016 develop(bool, SimulateFullAddressSpace, false, \
2017 "Simulates a very populated, fragmented address space; no " \
2018 "targeted reservations will succeed.") \
2019 \
2020 product(bool, ProfileExceptionHandlers, true, \
2021 "Profile exception handlers") \
2022 \
2023 product(bool, AlwaysRecordEvolDependencies, true, EXPERIMENTAL, \
2024 "Unconditionally record nmethod dependencies on class " \
2025 "rewriting/transformation independently of the JVMTI " \
2026 "can_{retransform/redefine}_classes capabilities.") \
2027 \
2028 product(bool, UseSecondarySupersCache, true, DIAGNOSTIC, \
2029 "Use secondary supers cache during subtype checks.") \
2030 \
2031 product(bool, UseSecondarySupersTable, false, DIAGNOSTIC, \
2032 "Use hash table to lookup secondary supers.") \
2033 \
2034 product(bool, VerifySecondarySupers, false, DIAGNOSTIC, \
2035 "Check that linear and hashed secondary lookups return the same result.") \
2036 \
2037 product(bool, StressSecondarySupers, false, DIAGNOSTIC, \
2038 "Use a terrible hash function in order to generate many collisions.") \
2039 \
2040 product(bool, UseThreadsLockThrottleLock, true, DIAGNOSTIC, \
2041 "Use an extra lock during Thread start and exit to alleviate" \
2042 "contention on Threads_lock.") \
2043 \
2044 develop(uint, BinarySearchThreshold, 16, \
2045 "Minimal number of elements in a sorted collection to prefer" \
2046 "binary search over simple linear search." ) \
2047 \
2048 product(bool, UseAcmpFastPath, true, DIAGNOSTIC, \
2049 "Use fast path for acmp.") \
2050
2051 // end of RUNTIME_FLAGS
2052
2053 DECLARE_FLAGS(LP64_RUNTIME_FLAGS)
2054 DECLARE_ARCH_FLAGS(ARCH_FLAGS)
2055 DECLARE_FLAGS(RUNTIME_FLAGS)
2056 DECLARE_FLAGS(RUNTIME_OS_FLAGS)
2057
2058 #endif // SHARE_RUNTIME_GLOBALS_HPP