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src/hotspot/share/gc/shenandoah/shenandoahArguments.cpp

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  1 /*
  2  * Copyright (c) 2018, 2022, Red Hat, Inc. 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,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 #include "precompiled.hpp"
 26 #include "gc/shared/gcArguments.hpp"
 27 #include "gc/shared/tlab_globals.hpp"
 28 #include "gc/shared/workerPolicy.hpp"
 29 #include "gc/shenandoah/shenandoahArguments.hpp"
 30 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"

 31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 32 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
 33 #include "runtime/globals_extension.hpp"
 34 #include "runtime/java.hpp"
 35 #include "utilities/defaultStream.hpp"
 36 
 37 void ShenandoahArguments::initialize() {
 38 #if !(defined AARCH64 || defined AMD64 || defined IA32 || defined PPC64 || defined RISCV64)
 39   vm_exit_during_initialization("Shenandoah GC is not supported on this platform.");
 40 #endif
 41 
 42 #if 0 // leave this block as stepping stone for future platforms
 43   log_warning(gc)("Shenandoah GC is not fully supported on this platform:");
 44   log_warning(gc)("  concurrent modes are not supported, only STW cycles are enabled;");
 45   log_warning(gc)("  arch-specific barrier code is not implemented, disabling barriers;");
 46 
 47   FLAG_SET_DEFAULT(ShenandoahGCHeuristics,           "passive");
 48 
 49   FLAG_SET_DEFAULT(ShenandoahSATBBarrier,            false);
 50   FLAG_SET_DEFAULT(ShenandoahLoadRefBarrier,         false);
 51   FLAG_SET_DEFAULT(ShenandoahIUBarrier,              false);
 52   FLAG_SET_DEFAULT(ShenandoahCASBarrier,             false);

 53   FLAG_SET_DEFAULT(ShenandoahCloneBarrier,           false);
 54 
 55   FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers,     false);
 56 #endif
 57   if (UseLargePages) {
 58     size_t large_page_size = os::large_page_size();
 59     if ((align_up(MaxHeapSize, large_page_size) / large_page_size) < ShenandoahHeapRegion::MIN_NUM_REGIONS) {
 60       warning("Large pages size (" SIZE_FORMAT "K) is too large to afford page-sized regions, disabling uncommit",
 61               os::large_page_size() / K);
 62       FLAG_SET_DEFAULT(ShenandoahUncommit, false);
 63     }
 64   }
 65 
 66   // Enable NUMA by default. While Shenandoah is not NUMA-aware, enabling NUMA makes
 67   // storage allocation code NUMA-aware.
 68   if (FLAG_IS_DEFAULT(UseNUMA)) {
 69     FLAG_SET_DEFAULT(UseNUMA, true);
 70   }
 71 







 72   // Set up default number of concurrent threads. We want to have cycles complete fast
 73   // enough, but we also do not want to steal too much CPU from the concurrently running
 74   // application. Using 1/4 of available threads for concurrent GC seems a good
 75   // compromise here.
 76   bool ergo_conc = FLAG_IS_DEFAULT(ConcGCThreads);
 77   if (ergo_conc) {
 78     FLAG_SET_DEFAULT(ConcGCThreads, MAX2(1, os::initial_active_processor_count() / 4));
 79   }
 80 
 81   if (ConcGCThreads == 0) {
 82     vm_exit_during_initialization("Shenandoah expects ConcGCThreads > 0, check -XX:ConcGCThreads=#");
 83   }
 84 
 85   // Set up default number of parallel threads. We want to have decent pauses performance
 86   // which would use parallel threads, but we also do not want to do too many threads
 87   // that will overwhelm the OS scheduler. Using 1/2 of available threads seems to be a fair
 88   // compromise here. Due to implementation constraints, it should not be lower than
 89   // the number of concurrent threads.
 90   bool ergo_parallel = FLAG_IS_DEFAULT(ParallelGCThreads);
 91   if (ergo_parallel) {

127       FLAG_SET_DEFAULT(LoopStripMiningIter, 1000);
128     }
129   }
130 #ifdef ASSERT
131   // C2 barrier verification is only reliable when all default barriers are enabled
132   if (ShenandoahVerifyOptoBarriers &&
133           (!FLAG_IS_DEFAULT(ShenandoahSATBBarrier)            ||
134            !FLAG_IS_DEFAULT(ShenandoahLoadRefBarrier)         ||
135            !FLAG_IS_DEFAULT(ShenandoahIUBarrier)              ||
136            !FLAG_IS_DEFAULT(ShenandoahCASBarrier)             ||
137            !FLAG_IS_DEFAULT(ShenandoahCloneBarrier)
138           )) {
139     warning("Unusual barrier configuration, disabling C2 barrier verification");
140     FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers, false);
141   }
142 #else
143   guarantee(!ShenandoahVerifyOptoBarriers, "Should be disabled");
144 #endif // ASSERT
145 #endif // COMPILER2
146 




147   // Record more information about previous cycles for improved debugging pleasure
148   if (FLAG_IS_DEFAULT(LogEventsBufferEntries)) {
149     FLAG_SET_DEFAULT(LogEventsBufferEntries, 250);
150   }
151 
152   if ((InitialHeapSize == MaxHeapSize) && ShenandoahUncommit) {
153     log_info(gc)("Min heap equals to max heap, disabling ShenandoahUncommit");
154     FLAG_SET_DEFAULT(ShenandoahUncommit, false);
155   }
156 
157   // If class unloading is disabled, no unloading for concurrent cycles as well.
158   if (!ClassUnloading) {
159     FLAG_SET_DEFAULT(ClassUnloadingWithConcurrentMark, false);
160   }
161 
162   // TLAB sizing policy makes resizing decisions before each GC cycle. It averages
163   // historical data, assigning more recent data the weight according to TLABAllocationWeight.
164   // Current default is good for generational collectors that run frequent young GCs.
165   // With Shenandoah, GC cycles are much less frequent, so we need we need sizing policy
166   // to converge faster over smaller number of resizing decisions.
167   if (FLAG_IS_DEFAULT(TLABAllocationWeight)) {
168     FLAG_SET_DEFAULT(TLABAllocationWeight, 90);
169   }
170 }
171 
172 size_t ShenandoahArguments::conservative_max_heap_alignment() {
173   size_t align = ShenandoahMaxRegionSize;
174   if (UseLargePages) {
175     align = MAX2(align, os::large_page_size());
176   }
177   return align;
178 }
179 
180 void ShenandoahArguments::initialize_alignments() {


181   // Need to setup sizes early to get correct alignments.
182   MaxHeapSize = ShenandoahHeapRegion::setup_sizes(MaxHeapSize);
183 
184   // This is expected by our algorithm for ShenandoahHeap::heap_region_containing().
185   size_t align = ShenandoahHeapRegion::region_size_bytes();
186   if (UseLargePages) {
187     align = MAX2(align, os::large_page_size());
188   }
189   SpaceAlignment = align;
190   HeapAlignment = align;
191 }
192 
193 CollectedHeap* ShenandoahArguments::create_heap() {



194   return new ShenandoahHeap(new ShenandoahCollectorPolicy());
195 }

  1 /*
  2  * Copyright (c) 2018, 2022, Red Hat, Inc. All rights reserved.
  3  * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
  4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  5  *
  6  * This code is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 only, as
  8  * published by the Free Software Foundation.
  9  *
 10  * This code is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 13  * version 2 for more details (a copy is included in the LICENSE file that
 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
 23  *
 24  */
 25 
 26 #include "precompiled.hpp"
 27 #include "gc/shared/gcArguments.hpp"
 28 #include "gc/shared/tlab_globals.hpp"
 29 #include "gc/shared/workerPolicy.hpp"
 30 #include "gc/shenandoah/shenandoahArguments.hpp"
 31 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
 32 #include "gc/shenandoah/shenandoahGenerationalHeap.hpp"
 33 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 34 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
 35 #include "runtime/globals_extension.hpp"
 36 #include "runtime/java.hpp"
 37 #include "utilities/defaultStream.hpp"
 38 
 39 void ShenandoahArguments::initialize() {
 40 #if !(defined AARCH64 || defined AMD64 || defined IA32 || defined PPC64 || defined RISCV64)
 41   vm_exit_during_initialization("Shenandoah GC is not supported on this platform.");
 42 #endif
 43 
 44 #if 0 // leave this block as stepping stone for future platforms
 45   log_warning(gc)("Shenandoah GC is not fully supported on this platform:");
 46   log_warning(gc)("  concurrent modes are not supported, only STW cycles are enabled;");
 47   log_warning(gc)("  arch-specific barrier code is not implemented, disabling barriers;");
 48 
 49   FLAG_SET_DEFAULT(ShenandoahGCHeuristics,           "passive");
 50 
 51   FLAG_SET_DEFAULT(ShenandoahSATBBarrier,            false);
 52   FLAG_SET_DEFAULT(ShenandoahLoadRefBarrier,         false);
 53   FLAG_SET_DEFAULT(ShenandoahIUBarrier,              false);
 54   FLAG_SET_DEFAULT(ShenandoahCASBarrier,             false);
 55   FLAG_SET_DEFAULT(ShenandoahCardBarrier,            false);
 56   FLAG_SET_DEFAULT(ShenandoahCloneBarrier,           false);
 57 
 58   FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers,     false);
 59 #endif
 60   if (UseLargePages) {
 61     size_t large_page_size = os::large_page_size();
 62     if ((align_up(MaxHeapSize, large_page_size) / large_page_size) < ShenandoahHeapRegion::MIN_NUM_REGIONS) {
 63       warning("Large pages size (" SIZE_FORMAT "K) is too large to afford page-sized regions, disabling uncommit",
 64               os::large_page_size() / K);
 65       FLAG_SET_DEFAULT(ShenandoahUncommit, false);
 66     }
 67   }
 68 
 69   // Enable NUMA by default. While Shenandoah is not NUMA-aware, enabling NUMA makes
 70   // storage allocation code NUMA-aware.
 71   if (FLAG_IS_DEFAULT(UseNUMA)) {
 72     FLAG_SET_DEFAULT(UseNUMA, true);
 73   }
 74 
 75   // We use this as the time period for tracking minimum mutator utilization (MMU).
 76   // In generational mode, the MMU is used as a signal to adjust the size of the
 77   // young generation.
 78   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 79     FLAG_SET_DEFAULT(GCPauseIntervalMillis, 5000);
 80   }
 81 
 82   // Set up default number of concurrent threads. We want to have cycles complete fast
 83   // enough, but we also do not want to steal too much CPU from the concurrently running
 84   // application. Using 1/4 of available threads for concurrent GC seems a good
 85   // compromise here.
 86   bool ergo_conc = FLAG_IS_DEFAULT(ConcGCThreads);
 87   if (ergo_conc) {
 88     FLAG_SET_DEFAULT(ConcGCThreads, MAX2(1, os::initial_active_processor_count() / 4));
 89   }
 90 
 91   if (ConcGCThreads == 0) {
 92     vm_exit_during_initialization("Shenandoah expects ConcGCThreads > 0, check -XX:ConcGCThreads=#");
 93   }
 94 
 95   // Set up default number of parallel threads. We want to have decent pauses performance
 96   // which would use parallel threads, but we also do not want to do too many threads
 97   // that will overwhelm the OS scheduler. Using 1/2 of available threads seems to be a fair
 98   // compromise here. Due to implementation constraints, it should not be lower than
 99   // the number of concurrent threads.
100   bool ergo_parallel = FLAG_IS_DEFAULT(ParallelGCThreads);
101   if (ergo_parallel) {

137       FLAG_SET_DEFAULT(LoopStripMiningIter, 1000);
138     }
139   }
140 #ifdef ASSERT
141   // C2 barrier verification is only reliable when all default barriers are enabled
142   if (ShenandoahVerifyOptoBarriers &&
143           (!FLAG_IS_DEFAULT(ShenandoahSATBBarrier)            ||
144            !FLAG_IS_DEFAULT(ShenandoahLoadRefBarrier)         ||
145            !FLAG_IS_DEFAULT(ShenandoahIUBarrier)              ||
146            !FLAG_IS_DEFAULT(ShenandoahCASBarrier)             ||
147            !FLAG_IS_DEFAULT(ShenandoahCloneBarrier)
148           )) {
149     warning("Unusual barrier configuration, disabling C2 barrier verification");
150     FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers, false);
151   }
152 #else
153   guarantee(!ShenandoahVerifyOptoBarriers, "Should be disabled");
154 #endif // ASSERT
155 #endif // COMPILER2
156 
157   if (ShenandoahIUBarrier) {
158     assert(strcmp(ShenandoahGCMode, "generational"), "Generational mode does not support IU barrier");
159   }
160 
161   // Record more information about previous cycles for improved debugging pleasure
162   if (FLAG_IS_DEFAULT(LogEventsBufferEntries)) {
163     FLAG_SET_DEFAULT(LogEventsBufferEntries, 250);
164   }
165 
166   if ((InitialHeapSize == MaxHeapSize) && ShenandoahUncommit) {
167     log_info(gc)("Min heap equals to max heap, disabling ShenandoahUncommit");
168     FLAG_SET_DEFAULT(ShenandoahUncommit, false);
169   }
170 
171   // If class unloading is disabled, no unloading for concurrent cycles as well.
172   if (!ClassUnloading) {
173     FLAG_SET_DEFAULT(ClassUnloadingWithConcurrentMark, false);
174   }
175 
176   // TLAB sizing policy makes resizing decisions before each GC cycle. It averages
177   // historical data, assigning more recent data the weight according to TLABAllocationWeight.
178   // Current default is good for generational collectors that run frequent young GCs.
179   // With Shenandoah, GC cycles are much less frequent, so we need we need sizing policy
180   // to converge faster over smaller number of resizing decisions.
181   if (FLAG_IS_DEFAULT(TLABAllocationWeight)) {
182     FLAG_SET_DEFAULT(TLABAllocationWeight, 90);
183   }
184 }
185 
186 size_t ShenandoahArguments::conservative_max_heap_alignment() {
187   size_t align = ShenandoahMaxRegionSize;
188   if (UseLargePages) {
189     align = MAX2(align, os::large_page_size());
190   }
191   return align;
192 }
193 
194 void ShenandoahArguments::initialize_alignments() {
195   CardTable::initialize_card_size();
196 
197   // Need to setup sizes early to get correct alignments.
198   MaxHeapSize = ShenandoahHeapRegion::setup_sizes(MaxHeapSize);
199 
200   // This is expected by our algorithm for ShenandoahHeap::heap_region_containing().
201   size_t align = ShenandoahHeapRegion::region_size_bytes();
202   if (UseLargePages) {
203     align = MAX2(align, os::large_page_size());
204   }
205   SpaceAlignment = align;
206   HeapAlignment = align;
207 }
208 
209 CollectedHeap* ShenandoahArguments::create_heap() {
210   if (strcmp(ShenandoahGCMode, "generational") == 0) {
211     return new ShenandoahGenerationalHeap(new ShenandoahCollectorPolicy());
212   }
213   return new ShenandoahHeap(new ShenandoahCollectorPolicy());
214 }
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