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8150839: Adjust the number of compiler threads for 32-bit platforms

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Set the number of compiler threads to 3 on 32-bit platforms.

Reviewed-by: iveresov
This commit is contained in:
Zoltan Majo 2016-03-04 08:53:59 +01:00
parent 40fe96de0d
commit d30d687178
3 changed files with 22 additions and 1 deletions
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15
hotspot/src/share/vm/runtime/advancedThresholdPolicy.cpp
View file

@ -42,17 +42,30 @@ void AdvancedThresholdPolicy::print_specific(EventType type, methodHandle mh, me
}
void AdvancedThresholdPolicy::initialize() {
int count = CICompilerCount;
#ifdef _LP64
// Turn on ergonomic compiler count selection
if (FLAG_IS_DEFAULT(CICompilerCountPerCPU) && FLAG_IS_DEFAULT(CICompilerCount)) {
FLAG_SET_DEFAULT(CICompilerCountPerCPU, true);
}
int count = CICompilerCount;
if (CICompilerCountPerCPU) {
// Simple log n seems to grow too slowly for tiered, try something faster: log n * log log n
int log_cpu = log2_intptr(os::active_processor_count());
int loglog_cpu = log2_intptr(MAX2(log_cpu, 1));
count = MAX2(log_cpu * loglog_cpu, 1) * 3 / 2;
}
#else
// On 32-bit systems, the number of compiler threads is limited to 3.
// On these systems, the virtual address space available to the JVM
// is usually limited to 2-4 GB (the exact value depends on the platform).
// As the compilers (especially C2) can consume a large amount of
// memory, scaling the number of compiler threads with the number of
// available cores can result in the exhaustion of the address space
/// available to the VM and thus cause the VM to crash.
if (FLAG_IS_DEFAULT(CICompilerCount)) {
count = 3;
}
#endif
set_c1_count(MAX2(count / 3, 1));
set_c2_count(MAX2(count - c1_count(), 1));

2
hotspot/src/share/vm/runtime/arguments.cpp
View file

@ -2472,9 +2472,11 @@ bool Arguments::check_vm_args_consistency() {
status = false;
}
#ifdef _LP64
if (!FLAG_IS_DEFAULT(CICompilerCount) && !FLAG_IS_DEFAULT(CICompilerCountPerCPU) && CICompilerCountPerCPU) {
warning("The VM option CICompilerCountPerCPU overrides CICompilerCount.");
}
#endif
#ifndef SUPPORT_RESERVED_STACK_AREA
if (StackReservedPages != 0) {

6
hotspot/src/share/vm/runtime/simpleThresholdPolicy.cpp
View file

@ -138,9 +138,15 @@ void SimpleThresholdPolicy::initialize() {
FLAG_SET_DEFAULT(CICompilerCount, 3);
}
int count = CICompilerCount;
#ifdef _LP64
// On 64-bit systems, scale the number of compiler threads with
// the number of cores available on the system. Scaling is not
// performed on 32-bit systems because it can lead to exhaustion
// of the virtual memory address space available to the JVM.
if (CICompilerCountPerCPU) {
count = MAX2(log2_intptr(os::active_processor_count()), 1) * 3 / 2;
}
#endif
set_c1_count(MAX2(count / 3, 1));
set_c2_count(MAX2(count - c1_count(), 1));
FLAG_SET_ERGO(intx, CICompilerCount, c1_count() + c2_count());