| /* |
| * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "gc/shared/gcArguments.hpp" |
| #include "gc/shared/workerPolicy.hpp" |
| #include "gc/shenandoah/shenandoahArguments.hpp" |
| #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" |
| #include "gc/shenandoah/shenandoahHeap.inline.hpp" |
| #include "gc/shenandoah/shenandoahHeapRegion.hpp" |
| #include "runtime/globals_extension.hpp" |
| #include "runtime/java.hpp" |
| #include "utilities/defaultStream.hpp" |
| |
| void ShenandoahArguments::initialize() { |
| #if !(defined AARCH64 || defined AMD64 || defined IA32) |
| vm_exit_during_initialization("Shenandoah GC is not supported on this platform."); |
| #endif |
| |
| #if 0 // leave this block as stepping stone for future platforms |
| log_warning(gc)("Shenandoah GC is not fully supported on this platform:"); |
| log_warning(gc)(" concurrent modes are not supported, only STW cycles are enabled;"); |
| log_warning(gc)(" arch-specific barrier code is not implemented, disabling barriers;"); |
| |
| FLAG_SET_DEFAULT(ShenandoahGCHeuristics, "passive"); |
| |
| FLAG_SET_DEFAULT(ShenandoahSATBBarrier, false); |
| FLAG_SET_DEFAULT(ShenandoahLoadRefBarrier, false); |
| FLAG_SET_DEFAULT(ShenandoahStoreValEnqueueBarrier, false); |
| FLAG_SET_DEFAULT(ShenandoahCASBarrier, false); |
| FLAG_SET_DEFAULT(ShenandoahCloneBarrier, false); |
| |
| FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers, false); |
| #endif |
| |
| if (UseLargePages && (MaxHeapSize / os::large_page_size()) < ShenandoahHeapRegion::MIN_NUM_REGIONS) { |
| warning("Large pages size (" SIZE_FORMAT "K) is too large to afford page-sized regions, disabling uncommit", |
| os::large_page_size() / K); |
| FLAG_SET_DEFAULT(ShenandoahUncommit, false); |
| } |
| |
| // Enable NUMA by default. While Shenandoah is not NUMA-aware, enabling NUMA makes |
| // storage allocation code NUMA-aware. |
| if (FLAG_IS_DEFAULT(UseNUMA)) { |
| FLAG_SET_DEFAULT(UseNUMA, true); |
| } |
| |
| // Set up default number of concurrent threads. We want to have cycles complete fast |
| // enough, but we also do not want to steal too much CPU from the concurrently running |
| // application. Using 1/4 of available threads for concurrent GC seems a good |
| // compromise here. |
| bool ergo_conc = FLAG_IS_DEFAULT(ConcGCThreads); |
| if (ergo_conc) { |
| FLAG_SET_DEFAULT(ConcGCThreads, MAX2(1, os::initial_active_processor_count() / 4)); |
| } |
| |
| if (ConcGCThreads == 0) { |
| vm_exit_during_initialization("Shenandoah expects ConcGCThreads > 0, check -XX:ConcGCThreads=#"); |
| } |
| |
| // Set up default number of parallel threads. We want to have decent pauses performance |
| // which would use parallel threads, but we also do not want to do too many threads |
| // that will overwhelm the OS scheduler. Using 1/2 of available threads seems to be a fair |
| // compromise here. Due to implementation constraints, it should not be lower than |
| // the number of concurrent threads. |
| bool ergo_parallel = FLAG_IS_DEFAULT(ParallelGCThreads); |
| if (ergo_parallel) { |
| FLAG_SET_DEFAULT(ParallelGCThreads, MAX2(1, os::initial_active_processor_count() / 2)); |
| } |
| |
| if (ParallelGCThreads == 0) { |
| vm_exit_during_initialization("Shenandoah expects ParallelGCThreads > 0, check -XX:ParallelGCThreads=#"); |
| } |
| |
| // Make sure ergonomic decisions do not break the thread count invariants. |
| // This may happen when user overrides one of the flags, but not the other. |
| // When that happens, we want to adjust the setting that was set ergonomically. |
| if (ParallelGCThreads < ConcGCThreads) { |
| if (ergo_conc && !ergo_parallel) { |
| FLAG_SET_DEFAULT(ConcGCThreads, ParallelGCThreads); |
| } else if (!ergo_conc && ergo_parallel) { |
| FLAG_SET_DEFAULT(ParallelGCThreads, ConcGCThreads); |
| } else if (ergo_conc && ergo_parallel) { |
| // Should not happen, check the ergonomic computation above. Fail with relevant error. |
| vm_exit_during_initialization("Shenandoah thread count ergonomic error"); |
| } else { |
| // User settings error, report and ask user to rectify. |
| vm_exit_during_initialization("Shenandoah expects ConcGCThreads <= ParallelGCThreads, check -XX:ParallelGCThreads, -XX:ConcGCThreads"); |
| } |
| } |
| |
| if (FLAG_IS_DEFAULT(ParallelRefProcEnabled)) { |
| FLAG_SET_DEFAULT(ParallelRefProcEnabled, true); |
| } |
| |
| if (ShenandoahRegionSampling && FLAG_IS_DEFAULT(PerfDataMemorySize)) { |
| // When sampling is enabled, max out the PerfData memory to get more |
| // Shenandoah data in, including Matrix. |
| FLAG_SET_DEFAULT(PerfDataMemorySize, 2048*K); |
| } |
| |
| #ifdef COMPILER2 |
| // Shenandoah cares more about pause times, rather than raw throughput. |
| if (FLAG_IS_DEFAULT(UseCountedLoopSafepoints)) { |
| FLAG_SET_DEFAULT(UseCountedLoopSafepoints, true); |
| if (FLAG_IS_DEFAULT(LoopStripMiningIter)) { |
| FLAG_SET_DEFAULT(LoopStripMiningIter, 1000); |
| } |
| } |
| #ifdef ASSERT |
| // C2 barrier verification is only reliable when all default barriers are enabled |
| if (ShenandoahVerifyOptoBarriers && |
| (!FLAG_IS_DEFAULT(ShenandoahSATBBarrier) || |
| !FLAG_IS_DEFAULT(ShenandoahLoadRefBarrier) || |
| !FLAG_IS_DEFAULT(ShenandoahStoreValEnqueueBarrier) || |
| !FLAG_IS_DEFAULT(ShenandoahCASBarrier) || |
| !FLAG_IS_DEFAULT(ShenandoahCloneBarrier) |
| )) { |
| warning("Unusual barrier configuration, disabling C2 barrier verification"); |
| FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers, false); |
| } |
| #else |
| guarantee(!ShenandoahVerifyOptoBarriers, "Should be disabled"); |
| #endif // ASSERT |
| #endif // COMPILER2 |
| |
| // Record more information about previous cycles for improved debugging pleasure |
| if (FLAG_IS_DEFAULT(LogEventsBufferEntries)) { |
| FLAG_SET_DEFAULT(LogEventsBufferEntries, 250); |
| } |
| |
| if ((InitialHeapSize == MaxHeapSize) && ShenandoahUncommit) { |
| log_info(gc)("Min heap equals to max heap, disabling ShenandoahUncommit"); |
| FLAG_SET_DEFAULT(ShenandoahUncommit, false); |
| } |
| |
| // If class unloading is disabled, no unloading for concurrent cycles as well. |
| if (!ClassUnloading) { |
| FLAG_SET_DEFAULT(ClassUnloadingWithConcurrentMark, false); |
| } |
| |
| // AOT is not supported yet |
| if (UseAOT) { |
| if (!FLAG_IS_DEFAULT(UseAOT)) { |
| warning("Shenandoah does not support AOT at this moment, disabling UseAOT"); |
| } |
| FLAG_SET_DEFAULT(UseAOT, false); |
| } |
| |
| // TLAB sizing policy makes resizing decisions before each GC cycle. It averages |
| // historical data, assigning more recent data the weight according to TLABAllocationWeight. |
| // Current default is good for generational collectors that run frequent young GCs. |
| // With Shenandoah, GC cycles are much less frequent, so we need we need sizing policy |
| // to converge faster over smaller number of resizing decisions. |
| if (FLAG_IS_DEFAULT(TLABAllocationWeight)) { |
| FLAG_SET_DEFAULT(TLABAllocationWeight, 90); |
| } |
| } |
| |
| size_t ShenandoahArguments::conservative_max_heap_alignment() { |
| size_t align = ShenandoahMaxRegionSize; |
| if (UseLargePages) { |
| align = MAX2(align, os::large_page_size()); |
| } |
| return align; |
| } |
| |
| void ShenandoahArguments::initialize_alignments() { |
| // Need to setup sizes early to get correct alignments. |
| ShenandoahHeapRegion::setup_sizes(MaxHeapSize); |
| |
| // This is expected by our algorithm for ShenandoahHeap::heap_region_containing(). |
| size_t align = ShenandoahHeapRegion::region_size_bytes(); |
| if (UseLargePages) { |
| align = MAX2(align, os::large_page_size()); |
| } |
| SpaceAlignment = align; |
| HeapAlignment = align; |
| } |
| |
| CollectedHeap* ShenandoahArguments::create_heap() { |
| return new ShenandoahHeap(new ShenandoahCollectorPolicy()); |
| } |