truffle: src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp comparison

comparison src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp @ 4831:7ca7be5a6a0b

7129271: G1: Interference from multiple threads in PrintGC/PrintGCDetails output Summary: During an initial mark pause, signal the Concurrent Mark thread after the pause output from PrintGC/PrintGCDetails is complete. Reviewed-by: tonyp, brutisso

author	johnc
date	Tue, 17 Jan 2012 10:21:43 -0800
parents	9509c20bba28
children	57025542827f

comparison

equal deleted inserted replaced

-:0b3d1ec6eaee
+:7ca7be5a6a0b
 HRSPhaseSetter x(HRSPhaseEvacuation);
 verify_region_sets_optional();
 verify_dirty_young_regions();
+// This call will decide whether this pause is an initial-mark
+// pause. If it is, during_initial_mark_pause() will return true
+// for the duration of this pause.
+g1_policy()->decide_on_conc_mark_initiation();
+// We do not allow initial-mark to be piggy-backed on a mixed GC.
+assert(!g1_policy()->during_initial_mark_pause() ||
+g1_policy()->gcs_are_young(), "sanity");
+// We also do not allow mixed GCs during marking.
+assert(!mark_in_progress() || g1_policy()->gcs_are_young(), "sanity");
+// Record whether this pause is an initial mark. When the current
+// thread has completed its logging output and it's safe to signal
+// the CM thread, the flag's value in the policy has been reset.
+bool should_start_conc_mark = g1_policy()->during_initial_mark_pause();
+// Inner scope for scope based logging, timers, and stats collection
 {
-// This call will decide whether this pause is an initial-mark
-// pause. If it is, during_initial_mark_pause() will return true
-// for the duration of this pause.
-g1_policy()->decide_on_conc_mark_initiation();
-// We do not allow initial-mark to be piggy-backed on a mixed GC.
-assert(!g1_policy()->during_initial_mark_pause() ||
-g1_policy()->gcs_are_young(), "sanity");
-// We also do not allow mixed GCs during marking.
-assert(!mark_in_progress() || g1_policy()->gcs_are_young(), "sanity");
 char verbose_str[128];
 sprintf(verbose_str, "GC pause ");
 if (g1_policy()->gcs_are_young()) {
 strcat(verbose_str, "(young)");
 } else {
 gclog_or_tty->print(" VerifyBeforeGC:");
 prepare_for_verify();
 Universe::verify(/* allow dirty */ false,
 /* silent      */ false,
 /* option      */ VerifyOption_G1UsePrevMarking);
 }
 COMPILER2_PRESENT(DerivedPointerTable::clear());
 // Please see comment in g1CollectedHeap.hpp and
 }
 if (g1_policy()->during_initial_mark_pause()) {
 concurrent_mark()->checkpointRootsInitialPost();
 set_marking_started();
-// CAUTION: after the doConcurrentMark() call below,
+// Note that we don't actually trigger the CM thread at
-// the concurrent marking thread(s) could be running
+// this point. We do that later when we're sure that
-// concurrently with us. Make sure that anything after
+// the current thread has completed its logging output.
-// this point does not assume that we are the only GC thread
-// running. Note: of course, the actual marking work will
-// not start until the safepoint itself is released in
-// ConcurrentGCThread::safepoint_desynchronize().
-doConcurrentMark();
 }
 allocate_dummy_regions();
 #if YOUNG_LIST_VERBOSE
 print_tracing_info();
 vm_exit(-1);
 }
 }
+// The closing of the inner scope, immediately above, will complete
+// the PrintGC logging output. The record_collection_pause_end() call
+// above will complete the logging output of PrintGCDetails.
+//
+// It is not yet to safe, however, to tell the concurrent mark to
+// start as we have some optional output below. We don't want the
+// output from the concurrent mark thread interfering with this
+// logging output either.
 _hrs.verify_optional();
 verify_region_sets_optional();
 TASKQUEUE_STATS_ONLY(if (ParallelGCVerbose) print_taskqueue_stats());
 TASKQUEUE_STATS_ONLY(reset_taskqueue_stats());
 if (G1SummarizeRSetStats &&
 (G1SummarizeRSetStatsPeriod > 0) &&
 (total_collections() % G1SummarizeRSetStatsPeriod == 0)) {
 g1_rem_set()->print_summary_info();
+}
+// It should now be safe to tell the concurrent mark thread to start
+// without its logging output interfering with the logging output
+// that came from the pause.
+if (should_start_conc_mark) {
+// CAUTION: after the doConcurrentMark() call below,
+// the concurrent marking thread(s) could be running
+// concurrently with us. Make sure that anything after
+// this point does not assume that we are the only GC thread
+// running. Note: of course, the actual marking work will
+// not start until the safepoint itself is released in
+// ConcurrentGCThread::safepoint_desynchronize().
+doConcurrentMark();
 }
 return true;
 }

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comparison src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp @ 4831:7ca7be5a6a0b