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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(ShenandoahCASBarrier,             false);

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







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

169 
170   // TLAB sizing policy makes resizing decisions before each GC cycle. It averages
171   // historical data, assigning more recent data the weight according to TLABAllocationWeight.
172   // Current default is good for generational collectors that run frequent young GCs.
173   // With Shenandoah, GC cycles are much less frequent, so we need we need sizing policy
174   // to converge faster over smaller number of resizing decisions.
175   if (FLAG_IS_DEFAULT(TLABAllocationWeight)) {
176     FLAG_SET_DEFAULT(TLABAllocationWeight, 90);
177   }
178 }
179 
180 size_t ShenandoahArguments::conservative_max_heap_alignment() {
181   size_t align = ShenandoahMaxRegionSize;
182   if (UseLargePages) {
183     align = MAX2(align, os::large_page_size());
184   }
185   return align;
186 }
187 
188 void ShenandoahArguments::initialize_alignments() {


189   // Need to setup sizes early to get correct alignments.
190   MaxHeapSize = ShenandoahHeapRegion::setup_sizes(MaxHeapSize);
191 
192   // This is expected by our algorithm for ShenandoahHeap::heap_region_containing().
193   size_t align = ShenandoahHeapRegion::region_size_bytes();
194   if (UseLargePages) {
195     align = MAX2(align, os::large_page_size());
196   }
197   SpaceAlignment = align;
198   HeapAlignment = align;
199 }
200 
201 CollectedHeap* ShenandoahArguments::create_heap() {
202   return new ShenandoahHeap(new ShenandoahCollectorPolicy());





203 }

  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(ShenandoahCASBarrier,             false);
 54   FLAG_SET_DEFAULT(ShenandoahCardBarrier,            false);
 55   FLAG_SET_DEFAULT(ShenandoahCloneBarrier,           false);
 56 
 57   FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers,     false);
 58 #endif
 59   if (UseLargePages) {
 60     size_t large_page_size = os::large_page_size();
 61     if ((align_up(MaxHeapSize, large_page_size) / large_page_size) < ShenandoahHeapRegion::MIN_NUM_REGIONS) {
 62       warning("Large pages size (" SIZE_FORMAT "K) is too large to afford page-sized regions, disabling uncommit",
 63               os::large_page_size() / K);
 64       FLAG_SET_DEFAULT(ShenandoahUncommit, false);
 65     }
 66   }
 67 
 68   // Enable NUMA by default. While Shenandoah is not NUMA-aware, enabling NUMA makes
 69   // storage allocation code NUMA-aware.
 70   if (FLAG_IS_DEFAULT(UseNUMA)) {
 71     FLAG_SET_DEFAULT(UseNUMA, true);
 72   }
 73 
 74   // We use this as the time period for tracking minimum mutator utilization (MMU).
 75   // In generational mode, the MMU is used as a signal to adjust the size of the
 76   // young generation.
 77   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 78     FLAG_SET_DEFAULT(GCPauseIntervalMillis, 5000);
 79   }
 80 
 81   // Set up default number of concurrent threads. We want to have cycles complete fast
 82   // enough, but we also do not want to steal too much CPU from the concurrently running
 83   // application. Using 1/4 of available threads for concurrent GC seems a good
 84   // compromise here.
 85   bool ergo_conc = FLAG_IS_DEFAULT(ConcGCThreads);
 86   if (ergo_conc) {
 87     FLAG_SET_DEFAULT(ConcGCThreads, MAX2(1, os::initial_active_processor_count() / 4));
 88   }
 89 
 90   if (ConcGCThreads == 0) {
 91     vm_exit_during_initialization("Shenandoah expects ConcGCThreads > 0, check -XX:ConcGCThreads=#");
 92   }
 93 
 94   // Set up default number of parallel threads. We want to have decent pauses performance
 95   // which would use parallel threads, but we also do not want to do too many threads
 96   // that will overwhelm the OS scheduler. Using 1/2 of available threads seems to be a fair
 97   // compromise here. Due to implementation constraints, it should not be lower than
 98   // the number of concurrent threads.
 99   bool ergo_parallel = FLAG_IS_DEFAULT(ParallelGCThreads);
100   if (ergo_parallel) {

179 
180   // TLAB sizing policy makes resizing decisions before each GC cycle. It averages
181   // historical data, assigning more recent data the weight according to TLABAllocationWeight.
182   // Current default is good for generational collectors that run frequent young GCs.
183   // With Shenandoah, GC cycles are much less frequent, so we need we need sizing policy
184   // to converge faster over smaller number of resizing decisions.
185   if (FLAG_IS_DEFAULT(TLABAllocationWeight)) {
186     FLAG_SET_DEFAULT(TLABAllocationWeight, 90);
187   }
188 }
189 
190 size_t ShenandoahArguments::conservative_max_heap_alignment() {
191   size_t align = ShenandoahMaxRegionSize;
192   if (UseLargePages) {
193     align = MAX2(align, os::large_page_size());
194   }
195   return align;
196 }
197 
198 void ShenandoahArguments::initialize_alignments() {
199   CardTable::initialize_card_size();
200 
201   // Need to setup sizes early to get correct alignments.
202   MaxHeapSize = ShenandoahHeapRegion::setup_sizes(MaxHeapSize);
203 
204   // This is expected by our algorithm for ShenandoahHeap::heap_region_containing().
205   size_t align = ShenandoahHeapRegion::region_size_bytes();
206   if (UseLargePages) {
207     align = MAX2(align, os::large_page_size());
208   }
209   SpaceAlignment = align;
210   HeapAlignment = align;
211 }
212 
213 CollectedHeap* ShenandoahArguments::create_heap() {
214   if (strcmp(ShenandoahGCMode, "generational") != 0) {
215     // Not generational
216     return new ShenandoahHeap(new ShenandoahCollectorPolicy());
217   } else {
218     return new ShenandoahGenerationalHeap(new ShenandoahCollectorPolicy());
219   }
220 }
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