# HG changeset patch # User jmasa # Date 1203729434 28800 # Node ID 28372612af5ec980b4407d2ead9f474c90a6c3c2 # Parent 173195ff483ac75a5ffcd3cbc76b31db3861b02f 6362677: Change parallel GC collector default number of parallel GC threads. Summary: Use the same default number of GC threads as used by ParNewGC and ConcMarkSweepGC (i.e., the 5/8th rule). Reviewed-by: ysr, tonyp diff -r 173195ff483a -r 28372612af5e src/cpu/sparc/vm/vm_version_sparc.cpp --- a/src/cpu/sparc/vm/vm_version_sparc.cpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/cpu/sparc/vm/vm_version_sparc.cpp Fri Feb 22 17:17:14 2008 -0800 @@ -28,6 +28,12 @@ int VM_Version::_features = VM_Version::unknown_m; const char* VM_Version::_features_str = ""; +bool VM_Version::is_niagara1_plus() { + // This is a placeholder until the real test is determined. + return is_niagara1() && + (os::processor_count() > maximum_niagara1_processor_count()); +} + void VM_Version::initialize() { _features = determine_features(); PrefetchCopyIntervalInBytes = prefetch_copy_interval_in_bytes(); @@ -160,3 +166,13 @@ void VM_Version::revert() { _features = saved_features; } + +unsigned int VM_Version::calc_parallel_worker_threads() { + unsigned int result; + if (is_niagara1_plus()) { + result = nof_parallel_worker_threads(5, 16, 8); + } else { + result = nof_parallel_worker_threads(5, 8, 8); + } + return result; +} diff -r 173195ff483a -r 28372612af5e src/cpu/sparc/vm/vm_version_sparc.hpp --- a/src/cpu/sparc/vm/vm_version_sparc.hpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/cpu/sparc/vm/vm_version_sparc.hpp Fri Feb 22 17:17:14 2008 -0800 @@ -64,6 +64,11 @@ static bool is_niagara1(int features) { return (features & niagara1_m) == niagara1_m; } + static int maximum_niagara1_processor_count() { return 32; } + // Returns true if the platform is in the niagara line and + // newer than the niagara1. + static bool is_niagara1_plus(); + public: // Initialization static void initialize(); @@ -129,4 +134,7 @@ // Override the Abstract_VM_Version implementation. static uint page_size_count() { return is_sun4v() ? 4 : 2; } + + // Calculates the number of parallel threads + static unsigned int calc_parallel_worker_threads(); }; diff -r 173195ff483a -r 28372612af5e src/share/vm/gc_implementation/parallelScavenge/generationSizer.hpp --- a/src/share/vm/gc_implementation/parallelScavenge/generationSizer.hpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/share/vm/gc_implementation/parallelScavenge/generationSizer.hpp Fri Feb 22 17:17:14 2008 -0800 @@ -39,10 +39,10 @@ // If the user hasn't explicitly set the number of worker // threads, set the count. - if (ParallelGCThreads == 0) { - assert(UseParallelGC, "Setting ParallelGCThreads without UseParallelGC"); - ParallelGCThreads = os::active_processor_count(); - } + assert(UseSerialGC || + !FLAG_IS_DEFAULT(ParallelGCThreads) || + (ParallelGCThreads > 0), + "ParallelGCThreads should be set before flag initialization"); // The survivor ratio's are calculated "raw", unlike the // default gc, which adds 2 to the ratio value. We need to diff -r 173195ff483a -r 28372612af5e src/share/vm/runtime/arguments.cpp --- a/src/share/vm/runtime/arguments.cpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/share/vm/runtime/arguments.cpp Fri Feb 22 17:17:14 2008 -0800 @@ -924,10 +924,18 @@ void Arguments::set_parnew_gc_flags() { assert(!UseSerialGC && !UseParallelGC, "control point invariant"); + // Turn off AdaptiveSizePolicy by default for parnew until it is + // complete. + if (UseParNewGC && + FLAG_IS_DEFAULT(UseAdaptiveSizePolicy)) { + FLAG_SET_DEFAULT(UseAdaptiveSizePolicy, false); + } + if (FLAG_IS_DEFAULT(UseParNewGC) && ParallelGCThreads > 1) { FLAG_SET_DEFAULT(UseParNewGC, true); } else if (UseParNewGC && ParallelGCThreads == 0) { - FLAG_SET_DEFAULT(ParallelGCThreads, nof_parallel_gc_threads()); + FLAG_SET_DEFAULT(ParallelGCThreads, + Abstract_VM_Version::parallel_worker_threads()); if (FLAG_IS_DEFAULT(ParallelGCThreads) && ParallelGCThreads == 1) { FLAG_SET_DEFAULT(UseParNewGC, false); } @@ -956,25 +964,6 @@ } } -// CAUTION: this code is currently shared by UseParallelGC, UseParNewGC and -// UseconcMarkSweepGC. Further tuning of individual collectors might -// dictate refinement on a per-collector basis. -int Arguments::nof_parallel_gc_threads() { - if (FLAG_IS_DEFAULT(ParallelGCThreads)) { - // For very large machines, there are diminishing returns - // for large numbers of worker threads. Instead of - // hogging the whole system, use 5/8ths of a worker for every - // processor after the first 8. For example, on a 72 cpu - // machine use 8 + (72 - 8) * (5/8) == 48 worker threads. - // This is just a start and needs further tuning and study in - // Tiger. - int ncpus = os::active_processor_count(); - return (ncpus <= 8) ? ncpus : 3 + ((ncpus * 5) / 8); - } else { - return ParallelGCThreads; - } -} - // Adjust some sizes to suit CMS and/or ParNew needs; these work well on // sparc/solaris for certain applications, but would gain from // further optimization and tuning efforts, and would almost @@ -984,26 +973,24 @@ return; } + assert(UseConcMarkSweepGC, "CMS is expected to be on here"); + // If we are using CMS, we prefer to UseParNewGC, // unless explicitly forbidden. - if (UseConcMarkSweepGC && !UseParNewGC && FLAG_IS_DEFAULT(UseParNewGC)) { - FLAG_SET_DEFAULT(UseParNewGC, true); + if (!UseParNewGC && FLAG_IS_DEFAULT(UseParNewGC)) { + FLAG_SET_ERGO(bool, UseParNewGC, true); } // Turn off AdaptiveSizePolicy by default for cms until it is - // complete. Also turn it off in general if the - // parnew collector has been selected. - if ((UseConcMarkSweepGC || UseParNewGC) && - FLAG_IS_DEFAULT(UseAdaptiveSizePolicy)) { + // complete. + if (FLAG_IS_DEFAULT(UseAdaptiveSizePolicy)) { FLAG_SET_DEFAULT(UseAdaptiveSizePolicy, false); } // In either case, adjust ParallelGCThreads and/or UseParNewGC // as needed. - set_parnew_gc_flags(); - - if (!UseConcMarkSweepGC) { - return; + if (UseParNewGC) { + set_parnew_gc_flags(); } // Now make adjustments for CMS @@ -1147,17 +1134,11 @@ FLAG_IS_DEFAULT(UseParallelGC)) { if (should_auto_select_low_pause_collector()) { FLAG_SET_ERGO(bool, UseConcMarkSweepGC, true); - set_cms_and_parnew_gc_flags(); } else { FLAG_SET_ERGO(bool, UseParallelGC, true); } no_shared_spaces(); } - - // This is here because the parallel collector could - // have been selected so this initialization should - // still be done. - set_parallel_gc_flags(); } } @@ -1170,6 +1151,9 @@ // If no heap maximum was requested explicitly, use some reasonable fraction // of the physical memory, up to a maximum of 1GB. if (UseParallelGC) { + FLAG_SET_ERGO(uintx, ParallelGCThreads, + Abstract_VM_Version::parallel_worker_threads()); + if (FLAG_IS_DEFAULT(MaxHeapSize)) { const uint64_t reasonable_fraction = os::physical_memory() / DefaultMaxRAMFraction; @@ -1312,6 +1296,31 @@ UseParallelOldGC)); } +// Check consistency of GC selection +bool Arguments::check_gc_consistency() { + bool status = true; + // Ensure that the user has not selected conflicting sets + // of collectors. [Note: this check is merely a user convenience; + // collectors over-ride each other so that only a non-conflicting + // set is selected; however what the user gets is not what they + // may have expected from the combination they asked for. It's + // better to reduce user confusion by not allowing them to + // select conflicting combinations. + uint i = 0; + if (UseSerialGC) i++; + if (UseConcMarkSweepGC || UseParNewGC) i++; + if (UseParallelGC || UseParallelOldGC) i++; + if (i > 1) { + jio_fprintf(defaultStream::error_stream(), + "Conflicting collector combinations in option list; " + "please refer to the release notes for the combinations " + "allowed\n"); + status = false; + } + + return status; +} + // Check the consistency of vm_init_args bool Arguments::check_vm_args_consistency() { // Method for adding checks for flag consistency. @@ -1354,14 +1363,14 @@ status = false; } - status &= verify_percentage(MaxLiveObjectEvacuationRatio, + status = status && verify_percentage(MaxLiveObjectEvacuationRatio, "MaxLiveObjectEvacuationRatio"); - status &= verify_percentage(AdaptiveSizePolicyWeight, + status = status && verify_percentage(AdaptiveSizePolicyWeight, "AdaptiveSizePolicyWeight"); - status &= verify_percentage(AdaptivePermSizeWeight, "AdaptivePermSizeWeight"); - status &= verify_percentage(ThresholdTolerance, "ThresholdTolerance"); - status &= verify_percentage(MinHeapFreeRatio, "MinHeapFreeRatio"); - status &= verify_percentage(MaxHeapFreeRatio, "MaxHeapFreeRatio"); + status = status && verify_percentage(AdaptivePermSizeWeight, "AdaptivePermSizeWeight"); + status = status && verify_percentage(ThresholdTolerance, "ThresholdTolerance"); + status = status && verify_percentage(MinHeapFreeRatio, "MinHeapFreeRatio"); + status = status && verify_percentage(MaxHeapFreeRatio, "MaxHeapFreeRatio"); if (MinHeapFreeRatio > MaxHeapFreeRatio) { jio_fprintf(defaultStream::error_stream(), @@ -1377,14 +1386,14 @@ MarkSweepAlwaysCompactCount = 1; // Move objects every gc. } - status &= verify_percentage(GCHeapFreeLimit, "GCHeapFreeLimit"); - status &= verify_percentage(GCTimeLimit, "GCTimeLimit"); + status = status && verify_percentage(GCHeapFreeLimit, "GCHeapFreeLimit"); + status = status && verify_percentage(GCTimeLimit, "GCTimeLimit"); if (GCTimeLimit == 100) { // Turn off gc-overhead-limit-exceeded checks FLAG_SET_DEFAULT(UseGCOverheadLimit, false); } - status &= verify_percentage(GCHeapFreeLimit, "GCHeapFreeLimit"); + status = status && verify_percentage(GCHeapFreeLimit, "GCHeapFreeLimit"); // Check user specified sharing option conflict with Parallel GC bool cannot_share = (UseConcMarkSweepGC || UseParallelGC || @@ -1402,24 +1411,7 @@ } } - // Ensure that the user has not selected conflicting sets - // of collectors. [Note: this check is merely a user convenience; - // collectors over-ride each other so that only a non-conflicting - // set is selected; however what the user gets is not what they - // may have expected from the combination they asked for. It's - // better to reduce user confusion by not allowing them to - // select conflicting combinations. - uint i = 0; - if (UseSerialGC) i++; - if (UseConcMarkSweepGC || UseParNewGC) i++; - if (UseParallelGC || UseParallelOldGC) i++; - if (i > 1) { - jio_fprintf(defaultStream::error_stream(), - "Conflicting collector combinations in option list; " - "please refer to the release notes for the combinations " - "allowed\n"); - status = false; - } + status = status && check_gc_consistency(); if (_has_alloc_profile) { if (UseParallelGC || UseParallelOldGC) { @@ -1451,15 +1443,15 @@ "allocation buffers\n(-XX:+UseTLAB).\n"); status = false; } else { - status &= verify_percentage(CMSIncrementalDutyCycle, + status = status && verify_percentage(CMSIncrementalDutyCycle, "CMSIncrementalDutyCycle"); - status &= verify_percentage(CMSIncrementalDutyCycleMin, + status = status && verify_percentage(CMSIncrementalDutyCycleMin, "CMSIncrementalDutyCycleMin"); - status &= verify_percentage(CMSIncrementalSafetyFactor, + status = status && verify_percentage(CMSIncrementalSafetyFactor, "CMSIncrementalSafetyFactor"); - status &= verify_percentage(CMSIncrementalOffset, + status = status && verify_percentage(CMSIncrementalOffset, "CMSIncrementalOffset"); - status &= verify_percentage(CMSExpAvgFactor, + status = status && verify_percentage(CMSExpAvgFactor, "CMSExpAvgFactor"); // If it was not set on the command line, set // CMSInitiatingOccupancyFraction to 1 so icms can initiate cycles early. @@ -2064,7 +2056,8 @@ // Enable parallel GC and adaptive generation sizing FLAG_SET_CMDLINE(bool, UseParallelGC, true); - FLAG_SET_DEFAULT(ParallelGCThreads, nof_parallel_gc_threads()); + FLAG_SET_DEFAULT(ParallelGCThreads, + Abstract_VM_Version::parallel_worker_threads()); // Encourage steady state memory management FLAG_SET_CMDLINE(uintx, ThresholdTolerance, 100); @@ -2451,15 +2444,25 @@ no_shared_spaces(); #endif // KERNEL - // Set some flags for ParallelGC if needed. - set_parallel_gc_flags(); - - // Set some flags for CMS and/or ParNew collectors, as needed. - set_cms_and_parnew_gc_flags(); - // Set flags based on ergonomics. set_ergonomics_flags(); + // Check the GC selections again. + if (!check_gc_consistency()) { + return JNI_EINVAL; + } + + if (UseParallelGC) { + // Set some flags for ParallelGC if needed. + set_parallel_gc_flags(); + } else if (UseConcMarkSweepGC) { + // Set some flags for CMS + set_cms_and_parnew_gc_flags(); + } else if (UseParNewGC) { + // Set some flags for ParNew + set_parnew_gc_flags(); + } + #ifdef SERIALGC assert(verify_serial_gc_flags(), "SerialGC unset"); #endif // SERIALGC @@ -2479,6 +2482,12 @@ CommandLineFlags::printSetFlags(); } +#ifdef ASSERT + if (PrintFlagsFinal) { + CommandLineFlags::printFlags(); + } +#endif + return JNI_OK; } diff -r 173195ff483a -r 28372612af5e src/share/vm/runtime/arguments.hpp --- a/src/share/vm/runtime/arguments.hpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/share/vm/runtime/arguments.hpp Fri Feb 22 17:17:14 2008 -0800 @@ -291,8 +291,6 @@ static bool _CIDynamicCompilePriority; static intx _Tier2CompileThreshold; - // GC processing - static int nof_parallel_gc_threads(); // CMS/ParNew garbage collectors static void set_parnew_gc_flags(); static void set_cms_and_parnew_gc_flags(); @@ -385,6 +383,8 @@ public: // Parses the arguments static jint parse(const JavaVMInitArgs* args); + // Check for consistency in the selection of the garbage collector. + static bool check_gc_consistency(); // Check consistecy or otherwise of VM argument settings static bool check_vm_args_consistency(); // Used by os_solaris diff -r 173195ff483a -r 28372612af5e src/share/vm/runtime/globals.hpp --- a/src/share/vm/runtime/globals.hpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/share/vm/runtime/globals.hpp Fri Feb 22 17:17:14 2008 -0800 @@ -1794,6 +1794,9 @@ "number of times a GC thread (minus the coordinator) " \ "will sleep while yielding before giving up and resuming GC") \ \ + notproduct(bool, PrintFlagsFinal, false, \ + "Print all command line flags after argument processing") \ + \ /* gc tracing */ \ manageable(bool, PrintGC, false, \ "Print message at garbage collect") \ diff -r 173195ff483a -r 28372612af5e src/share/vm/runtime/vm_version.cpp --- a/src/share/vm/runtime/vm_version.cpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/share/vm/runtime/vm_version.cpp Fri Feb 22 17:17:14 2008 -0800 @@ -52,6 +52,8 @@ int Abstract_VM_Version::_vm_minor_version = 0; int Abstract_VM_Version::_vm_build_number = 0; bool Abstract_VM_Version::_initialized = false; +int Abstract_VM_Version::_parallel_worker_threads = 0; +bool Abstract_VM_Version::_parallel_worker_threads_initialized = false; void Abstract_VM_Version::initialize() { if (_initialized) { @@ -210,3 +212,43 @@ } #endif } + +unsigned int Abstract_VM_Version::nof_parallel_worker_threads( + unsigned int num, + unsigned int den, + unsigned int switch_pt) { + if (FLAG_IS_DEFAULT(ParallelGCThreads)) { + assert(ParallelGCThreads == 0, "Default ParallelGCThreads is not 0"); + // For very large machines, there are diminishing returns + // for large numbers of worker threads. Instead of + // hogging the whole system, use a fraction of the workers for every + // processor after the first 8. For example, on a 72 cpu machine + // and a chosen fraction of 5/8 + // use 8 + (72 - 8) * (5/8) == 48 worker threads. + unsigned int ncpus = (unsigned int) os::active_processor_count(); + return (ncpus <= switch_pt) ? + ncpus : + (switch_pt + ((ncpus - switch_pt) * num) / den); + } else { + return ParallelGCThreads; + } +} + +unsigned int Abstract_VM_Version::calc_parallel_worker_threads() { + return nof_parallel_worker_threads(5, 8, 8); +} + + +// Does not set the _initialized flag since it is +// a global flag. +unsigned int Abstract_VM_Version::parallel_worker_threads() { + if (!_parallel_worker_threads_initialized) { + if (FLAG_IS_DEFAULT(ParallelGCThreads)) { + _parallel_worker_threads = VM_Version::calc_parallel_worker_threads(); + } else { + _parallel_worker_threads = ParallelGCThreads; + } + _parallel_worker_threads_initialized = true; + } + return _parallel_worker_threads; +} diff -r 173195ff483a -r 28372612af5e src/share/vm/runtime/vm_version.hpp --- a/src/share/vm/runtime/vm_version.hpp Thu Feb 21 11:03:54 2008 -0800 +++ b/src/share/vm/runtime/vm_version.hpp Fri Feb 22 17:17:14 2008 -0800 @@ -36,6 +36,12 @@ static int _vm_minor_version; static int _vm_build_number; static bool _initialized; + static int _parallel_worker_threads; + static bool _parallel_worker_threads_initialized; + + static unsigned int nof_parallel_worker_threads(unsigned int num, + unsigned int dem, + unsigned int switch_pt); public: static void initialize(); @@ -69,4 +75,13 @@ // subclasses should define new versions to hide this one as needed. Note // that the O/S may support more sizes, but at most this many are used. static uint page_size_count() { return 2; } + + // Returns the number of parallel threads to be used for VM + // work. If that number has not been calculated, do so and + // save it. Returns ParallelGCThreads if it is set on the + // command line. + static unsigned int parallel_worker_threads(); + // Calculates and returns the number of parallel threads. May + // be VM version specific. + static unsigned int calc_parallel_worker_threads(); };