6821700: tune VM flags for peak performance
Summary: Tune C2 flags default values for performance.
Reviewed-by: never, phh, iveresov, jmasa, ysr
/*
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//
// Sets the default values for platform dependent flags used by the runtime system.
// (see globals.hpp)
//
// For sparc we do not do call backs when a thread is in the interpreter, because the
// interpreter dispatch needs at least two instructions - first to load the dispatch address
// in a register, and second to jmp. The swapping of the dispatch table may occur _after_
// the load of the dispatch address and hence the jmp would still go to the location
// according to the prior table. So, we let the thread continue and let it block by itself.
define_pd_global(bool, DontYieldALot, true); // yield no more than 100 times per second
define_pd_global(bool, ConvertSleepToYield, false); // do not convert sleep(0) to yield. Helps GUI
define_pd_global(bool, ShareVtableStubs, false); // improves performance markedly for mtrt and compress
define_pd_global(bool, CountInterpCalls, false); // not implemented in the interpreter
define_pd_global(bool, NeedsDeoptSuspend, true); // register window machines need this
define_pd_global(bool, ImplicitNullChecks, true); // Generate code for implicit null checks
define_pd_global(bool, UncommonNullCast, true); // Uncommon-trap NULLs past to check cast
define_pd_global(intx, CodeEntryAlignment, 32);
define_pd_global(uintx, TLABSize, 0);
define_pd_global(uintx, NewSize, ScaleForWordSize((2048 * K) + (2 * (64 * K))));
define_pd_global(intx, SurvivorRatio, 8);
define_pd_global(intx, InlineFrequencyCount, 50); // we can use more inlining on the SPARC
define_pd_global(intx, InlineSmallCode, 1500);
#ifdef _LP64
// Stack slots are 2X larger in LP64 than in the 32 bit VM.
define_pd_global(intx, ThreadStackSize, 1024);
define_pd_global(intx, VMThreadStackSize, 1024);
#else
define_pd_global(intx, ThreadStackSize, 512);
define_pd_global(intx, VMThreadStackSize, 512);
#endif
define_pd_global(intx, StackYellowPages, 2);
define_pd_global(intx, StackRedPages, 1);
define_pd_global(intx, StackShadowPages, 3 DEBUG_ONLY(+1));
define_pd_global(intx, PreInflateSpin, 40); // Determined by running design center
define_pd_global(bool, RewriteBytecodes, true);
define_pd_global(bool, RewriteFrequentPairs, true);