6896099: Integrate CMS heap ergo with default heap sizing ergo
6627787: CMS: JVM refuses to start up with -Xms16m -Xmx16m
7000125: CMS: Anti-monotone young gen sizing with respect to maximum whole heap size specification
7027529: CMS: retire CMSUseOldDefaults flag
Summary: Simplify CMS heap sizing code, relying on ergonomic initial sizing consistent with other collectors for the most part, controlling only young gen sizing to rein in pause times. Make CMS young gen sizing default statically cpu-dependant. Remove inconsistencies wrt generation sizing and policy code, allowing for the fixing for 6627787 and 7000125. For 7027529, retire the flag CMSUseOldDefaults which had been introduced as a bridge from JDK 5 to JDK 6 a number of years ago.
Reviewed-by: brutisso, poonam
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#ifndef CPU_X86_VM_GLOBALS_X86_HPP
#define CPU_X86_VM_GLOBALS_X86_HPP
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
// Sets the default values for platform dependent flags used by the runtime system.
// (see globals.hpp)
define_pd_global(bool, ConvertSleepToYield, true);
define_pd_global(bool, ShareVtableStubs, true);
define_pd_global(bool, CountInterpCalls, true);
define_pd_global(bool, NeedsDeoptSuspend, false); // only 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
// See 4827828 for this change. There is no globals_core_i486.hpp. I can't
// assign a different value for C2 without touching a number of files. Use
// #ifdef to minimize the change as it's late in Mantis. -- FIXME.
// c1 doesn't have this problem because the fix to 4858033 assures us
// the the vep is aligned at CodeEntryAlignment whereas c2 only aligns
// the uep and the vep doesn't get real alignment but just slops on by
// only assured that the entry instruction meets the 5 byte size requirement.
#ifdef COMPILER2
define_pd_global(intx, CodeEntryAlignment, 32);
#else
define_pd_global(intx, CodeEntryAlignment, 16);
#endif // COMPILER2
define_pd_global(intx, OptoLoopAlignment, 16);
define_pd_global(intx, InlineFrequencyCount, 100);
define_pd_global(intx, InlineSmallCode, 1000);
define_pd_global(intx, StackYellowPages, 2);
define_pd_global(intx, StackRedPages, 1);
#ifdef AMD64
// Very large C++ stack frames using solaris-amd64 optimized builds
// due to lack of optimization caused by C++ compiler bugs
define_pd_global(intx, StackShadowPages, SOLARIS_ONLY(20) NOT_SOLARIS(6) DEBUG_ONLY(+2));
#else
define_pd_global(intx, StackShadowPages, 3 DEBUG_ONLY(+5));
#endif // AMD64
define_pd_global(intx, PreInflateSpin, 10);
define_pd_global(bool, RewriteBytecodes, true);
define_pd_global(bool, RewriteFrequentPairs, true);
define_pd_global(bool, UseMembar, false);
// GC Ergo Flags
define_pd_global(intx, CMSYoungGenPerWorker, 64*M); // default max size of CMS young gen, per GC worker thread
#endif // CPU_X86_VM_GLOBALS_X86_HPP