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8029190: VM_Version::determine_features() asserts on Fujitsu Sparc64 CPUs

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Fix code to allow testing on Fujitsu Sparc64 CPUs

Reviewed-by: kvn
This commit is contained in:
Volker Simonis 2013-12-02 11:12:32 +01:00
parent c5b9d5ccd3
commit f0010291f7
3 changed files with 28 additions and 19 deletions
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27
hotspot/src/cpu/sparc/vm/vm_version_sparc.cpp
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@ -89,6 +89,27 @@ void VM_Version::initialize() {
_supports_cx8 = has_v9();
_supports_atomic_getset4 = true; // swap instruction
// There are Fujitsu Sparc64 CPUs which support blk_init as well so
// we have to take this check out of the 'is_niagara()' block below.
if (has_blk_init()) {
// When using CMS or G1, we cannot use memset() in BOT updates
// because the sun4v/CMT version in libc_psr uses BIS which
// exposes "phantom zeros" to concurrent readers. See 6948537.
if (FLAG_IS_DEFAULT(UseMemSetInBOT) && (UseConcMarkSweepGC || UseG1GC)) {
FLAG_SET_DEFAULT(UseMemSetInBOT, false);
}
// Issue a stern warning if the user has explicitly set
// UseMemSetInBOT (it is known to cause issues), but allow
// use for experimentation and debugging.
if (UseConcMarkSweepGC || UseG1GC) {
if (UseMemSetInBOT) {
assert(!FLAG_IS_DEFAULT(UseMemSetInBOT), "Error");
warning("Experimental flag -XX:+UseMemSetInBOT is known to cause instability"
" on sun4v; please understand that you are using at your own risk!");
}
}
}
if (is_niagara()) {
// Indirect branch is the same cost as direct
if (FLAG_IS_DEFAULT(UseInlineCaches)) {
@ -98,12 +119,6 @@ void VM_Version::initialize() {
if (FLAG_IS_DEFAULT(OptoLoopAlignment)) {
FLAG_SET_DEFAULT(OptoLoopAlignment, 4);
}
// When using CMS or G1, we cannot use memset() in BOT updates
// because the sun4v/CMT version in libc_psr uses BIS which
// exposes "phantom zeros" to concurrent readers. See 6948537.
if (FLAG_IS_DEFAULT(UseMemSetInBOT) && (UseConcMarkSweepGC || UseG1GC)) {
FLAG_SET_DEFAULT(UseMemSetInBOT, false);
}
#ifdef _LP64
// 32-bit oops don't make sense for the 64-bit VM on sparc
// since the 32-bit VM has the same registers and smaller objects.