Mercurial > hg > truffle
diff src/share/vm/runtime/arguments.cpp @ 7451:ca0a78017dc7
8005396: Use ParNew with only one thread instead of DefNew as default for CMS on single CPU machines
Reviewed-by: jmasa, jcoomes
author | brutisso |
---|---|
date | Sun, 30 Dec 2012 08:47:52 +0100 |
parents | 442f942757c0 |
children | e0ab18eafbde |
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--- a/src/share/vm/runtime/arguments.cpp Thu Jan 03 16:28:22 2013 -0800 +++ b/src/share/vm/runtime/arguments.cpp Sun Dec 30 08:47:52 2012 +0100 @@ -1083,10 +1083,6 @@ } } -// If the user has chosen ParallelGCThreads > 0, we set UseParNewGC -// if it's not explictly set or unset. If the user has chosen -// UseParNewGC and not explicitly set ParallelGCThreads we -// set it, unless this is a single cpu machine. void Arguments::set_parnew_gc_flags() { assert(!UseSerialGC && !UseParallelOldGC && !UseParallelGC && !UseG1GC, "control point invariant"); @@ -1095,42 +1091,41 @@ // Turn off AdaptiveSizePolicy for parnew until it is complete. disable_adaptive_size_policy("UseParNewGC"); - if (ParallelGCThreads == 0) { - FLAG_SET_DEFAULT(ParallelGCThreads, - Abstract_VM_Version::parallel_worker_threads()); - if (ParallelGCThreads == 1) { - FLAG_SET_DEFAULT(UseParNewGC, false); - FLAG_SET_DEFAULT(ParallelGCThreads, 0); - } + if (FLAG_IS_DEFAULT(ParallelGCThreads)) { + FLAG_SET_DEFAULT(ParallelGCThreads, Abstract_VM_Version::parallel_worker_threads()); + assert(ParallelGCThreads > 0, "We should always have at least one thread by default"); + } else if (ParallelGCThreads == 0) { + jio_fprintf(defaultStream::error_stream(), + "The ParNew GC can not be combined with -XX:ParallelGCThreads=0\n"); + vm_exit(1); + } + + // By default YoungPLABSize and OldPLABSize are set to 4096 and 1024 respectively, + // these settings are default for Parallel Scavenger. For ParNew+Tenured configuration + // we set them to 1024 and 1024. + // See CR 6362902. + if (FLAG_IS_DEFAULT(YoungPLABSize)) { + FLAG_SET_DEFAULT(YoungPLABSize, (intx)1024); } - if (UseParNewGC) { - // By default YoungPLABSize and OldPLABSize are set to 4096 and 1024 respectively, - // these settings are default for Parallel Scavenger. For ParNew+Tenured configuration - // we set them to 1024 and 1024. - // See CR 6362902. - if (FLAG_IS_DEFAULT(YoungPLABSize)) { - FLAG_SET_DEFAULT(YoungPLABSize, (intx)1024); + if (FLAG_IS_DEFAULT(OldPLABSize)) { + FLAG_SET_DEFAULT(OldPLABSize, (intx)1024); + } + + // AlwaysTenure flag should make ParNew promote all at first collection. + // See CR 6362902. + if (AlwaysTenure) { + FLAG_SET_CMDLINE(uintx, MaxTenuringThreshold, 0); + } + // When using compressed oops, we use local overflow stacks, + // rather than using a global overflow list chained through + // the klass word of the object's pre-image. + if (UseCompressedOops && !ParGCUseLocalOverflow) { + if (!FLAG_IS_DEFAULT(ParGCUseLocalOverflow)) { + warning("Forcing +ParGCUseLocalOverflow: needed if using compressed references"); } - if (FLAG_IS_DEFAULT(OldPLABSize)) { - FLAG_SET_DEFAULT(OldPLABSize, (intx)1024); - } - - // AlwaysTenure flag should make ParNew promote all at first collection. - // See CR 6362902. - if (AlwaysTenure) { - FLAG_SET_CMDLINE(uintx, MaxTenuringThreshold, 0); - } - // When using compressed oops, we use local overflow stacks, - // rather than using a global overflow list chained through - // the klass word of the object's pre-image. - if (UseCompressedOops && !ParGCUseLocalOverflow) { - if (!FLAG_IS_DEFAULT(ParGCUseLocalOverflow)) { - warning("Forcing +ParGCUseLocalOverflow: needed if using compressed references"); - } - FLAG_SET_DEFAULT(ParGCUseLocalOverflow, true); - } - assert(ParGCUseLocalOverflow || !UseCompressedOops, "Error"); + FLAG_SET_DEFAULT(ParGCUseLocalOverflow, true); } + assert(ParGCUseLocalOverflow || !UseCompressedOops, "Error"); } // Adjust some sizes to suit CMS and/or ParNew needs; these work well on