src/share/vm/memory/sharedHeap.cpp
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rev 4769 : 8015237: Parallelize string table scanning during strong root processing
Summary: Parallelize the scanning of the intern string table by having each GC worker claim a given number of buckets.
Reviewed-by:
@@ -1,7 +1,7 @@
/*
- * 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -45,11 +45,10 @@
SH_PS_FlatProfiler_oops_do,
SH_PS_Management_oops_do,
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
};
@@ -125,10 +124,12 @@
SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* outer, bool activate)
: MarkScope(activate)
{
if (_active) {
outer->change_strong_roots_parity();
+ // Zero the claimed high water mark in the StringTable
+ StringTable::clear_par_claimed_index();
}
}
SharedHeap::StrongRootsScope::~StrongRootsScope() {
// nothing particular
@@ -152,18 +153,20 @@
Universe::oops_do(roots);
}
// 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))
FlatProfiler::oops_do(roots);
if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
@@ -187,12 +190,16 @@
} else if (so & SO_SystemClasses) {
ClassLoaderDataGraph::always_strong_oops_do(roots, klass_closure, !is_scavenging);
}
}
- if (!_process_strong_tasks->is_task_claimed(SH_PS_StringTable_oops_do)) {
+ // 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);
}
}
if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {