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8015237: Parallelize string table scanning during strong root processing

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Parallelize the scanning of the intern string table by having each GC worker claim a given number of buckets. Changes were also reviewed by Per Liden <per.liden@oracle.com>.

Reviewed-by: tschatzl, stefank, twisti
This commit is contained in:
John Cuthbertson 2013-06-18 12:31:07 -07:00
parent f18e968d43
commit 5382e0759e
3 changed files with 63 additions and 10 deletions
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19
hotspot/src/share/vm/memory/sharedHeap.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -47,7 +47,6 @@ enum SH_process_strong_roots_tasks {
SH_PS_SystemDictionary_oops_do,
SH_PS_ClassLoaderDataGraph_oops_do,
SH_PS_jvmti_oops_do,
SH_PS_StringTable_oops_do,
SH_PS_CodeCache_oops_do,
// Leave this one last.
SH_PS_NumElements
@ -127,6 +126,8 @@ SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* outer, bool activate)
{
if (_active) {
outer->change_strong_roots_parity();
// Zero the claimed high water mark in the StringTable
StringTable::clear_parallel_claimed_index();
}
}
@ -154,14 +155,16 @@ void SharedHeap::process_strong_roots(bool activate_scope,
// Global (strong) JNI handles
if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
JNIHandles::oops_do(roots);
// All threads execute this; the individual threads are task groups.
CLDToOopClosure roots_from_clds(roots);
CLDToOopClosure* roots_from_clds_p = (is_scavenging ? NULL : &roots_from_clds);
if (ParallelGCThreads > 0) {
Threads::possibly_parallel_oops_do(roots, roots_from_clds_p ,code_roots);
if (CollectedHeap::use_parallel_gc_threads()) {
Threads::possibly_parallel_oops_do(roots, roots_from_clds_p, code_roots);
} else {
Threads::oops_do(roots, roots_from_clds_p, code_roots);
}
if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
ObjectSynchronizer::oops_do(roots);
if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
@ -189,8 +192,12 @@ void SharedHeap::process_strong_roots(bool activate_scope,
}
}
if (!_process_strong_tasks->is_task_claimed(SH_PS_StringTable_oops_do)) {
if (so & SO_Strings) {
// All threads execute the following. A specific chunk of buckets
// from the StringTable are the individual tasks.
if (so & SO_Strings) {
if (CollectedHeap::use_parallel_gc_threads()) {
StringTable::possibly_parallel_oops_do(roots);
} else {
StringTable::oops_do(roots);
}
}