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comparison src/share/vm/runtime/thread.cpp @ 4095:bca17e38de00

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6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads Summary: Select number of GC threads dynamically based on heap usage and number of Java threads Reviewed-by: johnc, ysr, jcoomes
author jmasa
date Tue, 09 Aug 2011 10:16:01 -0700
parents b20d64f83668
children 04b9a2566eec 94ec88ca68e2
comparison
equal deleted inserted replaced
4094:3a298e04d914 4095:bca17e38de00
776 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 776 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
777 if (res == thread_parity) { 777 if (res == thread_parity) {
778 return true; 778 return true;
779 } else { 779 } else {
780 guarantee(res == strong_roots_parity, "Or else what?"); 780 guarantee(res == strong_roots_parity, "Or else what?");
781 assert(SharedHeap::heap()->n_par_threads() > 0, 781 assert(SharedHeap::heap()->workers()->active_workers() > 0,
782 "Should only fail when parallel."); 782 "Should only fail when parallel.");
783 return false; 783 return false;
784 } 784 }
785 } 785 }
786 assert(SharedHeap::heap()->n_par_threads() > 0, 786 assert(SharedHeap::heap()->workers()->active_workers() > 0,
787 "Should only fail when parallel."); 787 "Should only fail when parallel.");
788 return false; 788 return false;
789 } 789 }
790 790
791 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 791 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3937 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) { 3937 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3938 // Introduce a mechanism allowing parallel threads to claim threads as 3938 // Introduce a mechanism allowing parallel threads to claim threads as
3939 // root groups. Overhead should be small enough to use all the time, 3939 // root groups. Overhead should be small enough to use all the time,
3940 // even in sequential code. 3940 // even in sequential code.
3941 SharedHeap* sh = SharedHeap::heap(); 3941 SharedHeap* sh = SharedHeap::heap();
3942 bool is_par = (sh->n_par_threads() > 0); 3942 // Cannot yet substitute active_workers for n_par_threads
3943 // because of G1CollectedHeap::verify() use of
3944 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
3945 // turn off parallelism in process_strong_roots while active_workers
3946 // is being used for parallelism elsewhere.
3947 bool is_par = sh->n_par_threads() > 0;
3948 assert(!is_par ||
3949 (SharedHeap::heap()->n_par_threads() ==
3950 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
3943 int cp = SharedHeap::heap()->strong_roots_parity(); 3951 int cp = SharedHeap::heap()->strong_roots_parity();
3944 ALL_JAVA_THREADS(p) { 3952 ALL_JAVA_THREADS(p) {
3945 if (p->claim_oops_do(is_par, cp)) { 3953 if (p->claim_oops_do(is_par, cp)) {
3946 p->oops_do(f, cf); 3954 p->oops_do(f, cf);
3947 } 3955 }