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8027295: Free CSet takes ~50% of young pause time

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Improve fast card cache iteration and avoid taking locks when freeing the collection set.

Reviewed-by: brutisso
This commit is contained in:
Thomas Schatzl 2014-03-17 10:13:18 +01:00
parent cde8aa670b
commit d3e28ca682
7 changed files with 54 additions and 13 deletions
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9
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
View file

@ -5939,7 +5939,8 @@ void G1CollectedHeap::evacuate_collection_set(EvacuationInfo& evacuation_info) {
void G1CollectedHeap::free_region(HeapRegion* hr,
FreeRegionList* free_list,
bool par) {
bool par,
bool locked) {
assert(!hr->isHumongous(), "this is only for non-humongous regions");
assert(!hr->is_empty(), "the region should not be empty");
assert(free_list != NULL, "pre-condition");
@ -5950,7 +5951,7 @@ void G1CollectedHeap::free_region(HeapRegion* hr,
if (!hr->is_young()) {
_cg1r->hot_card_cache()->reset_card_counts(hr);
}
hr->hr_clear(par, true /* clear_space */);
hr->hr_clear(par, true /* clear_space */, locked /* locked */);
free_list->add_as_head(hr);
}
@ -6159,7 +6160,7 @@ void G1CollectedHeap::free_collection_set(HeapRegion* cs_head, EvacuationInfo& e
}
}
rs_lengths += cur->rem_set()->occupied();
rs_lengths += cur->rem_set()->occupied_locked();
HeapRegion* next = cur->next_in_collection_set();
assert(cur->in_collection_set(), "bad CS");
@ -6193,7 +6194,7 @@ void G1CollectedHeap::free_collection_set(HeapRegion* cs_head, EvacuationInfo& e
// And the region is empty.
assert(!used_mr.is_empty(), "Should not have empty regions in a CS.");
pre_used += cur->used();
free_region(cur, &local_free_list, false /* par */);
free_region(cur, &local_free_list, false /* par */, true /* locked */);
} else {
cur->uninstall_surv_rate_group();
if (cur->is_young()) {

5
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp
View file

@ -763,9 +763,12 @@ public:
// list later). The used bytes of freed regions are accumulated in
// pre_used. If par is true, the region's RSet will not be freed
// up. The assumption is that this will be done later.
// The locked parameter indicates if the caller has already taken
// care of proper synchronization. This may allow some optimizations.
void free_region(HeapRegion* hr,
FreeRegionList* free_list,
bool par);
bool par,
bool locked = false);
// Frees a humongous region by collapsing it into individual regions
// and calling free_region() for each of them. The freed regions

4
hotspot/src/share/vm/gc_implementation/g1/g1GCPhaseTimes.cpp
View file

@ -317,6 +317,10 @@ void G1GCPhaseTimes::print(double pause_time_sec) {
print_stats(2, "Free CSet",
(_recorded_young_free_cset_time_ms +
_recorded_non_young_free_cset_time_ms));
if (G1Log::finest()) {
print_stats(3, "Young Free CSet", _recorded_young_free_cset_time_ms);
print_stats(3, "Non-Young Free CSet", _recorded_non_young_free_cset_time_ms);
}
if (_cur_verify_after_time_ms > 0.0) {
print_stats(2, "Verify After", _cur_verify_after_time_ms);
}

10
hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2014, 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
@ -205,7 +205,7 @@ void HeapRegion::reset_after_compaction() {
init_top_at_mark_start();
}
void HeapRegion::hr_clear(bool par, bool clear_space) {
void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
assert(_humongous_type == NotHumongous,
"we should have already filtered out humongous regions");
assert(_humongous_start_region == NULL,
@ -223,7 +223,11 @@ void HeapRegion::hr_clear(bool par, bool clear_space) {
if (!par) {
// If this is parallel, this will be done later.
HeapRegionRemSet* hrrs = rem_set();
hrrs->clear();
if (locked) {
hrrs->clear_locked();
} else {
hrrs->clear();
}
_claimed = InitialClaimValue;
}
zero_marked_bytes();

2
hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp
View file

@ -596,7 +596,7 @@ class HeapRegion: public G1OffsetTableContigSpace {
void save_marks();
// Reset HR stuff to default values.
void hr_clear(bool par, bool clear_space);
void hr_clear(bool par, bool clear_space, bool locked = false);
void par_clear();
// Get the start of the unmarked area in this region.

3
hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp
View file

@ -731,7 +731,8 @@ size_t OtherRegionsTable::fl_mem_size() {
void OtherRegionsTable::clear_fcc() {
uint hrs_idx = hr()->hrs_index();
for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
uint num_par_remsets = HeapRegionRemSet::num_par_rem_sets();
for (uint i = 0; i < num_par_remsets; i++) {
_from_card_cache[i][hrs_idx] = -1;
}
}

34
hotspot/test/gc/g1/TestGCLogMessages.java
View file

@ -23,7 +23,7 @@
/*
* @test TestPrintGCDetails
* @bug 8035406
* @bug 8035406 8027295
* @summary Ensure that the PrintGCDetails output for a minor GC with G1
* includes the expected necessary messages.
* @key gc
@ -38,13 +38,41 @@ public class TestGCLogMessages {
ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
"-Xmx10M",
"-XX:+PrintGCDetails",
GCTest.class.getName());
OutputAnalyzer output = new OutputAnalyzer(pb.start());
output.shouldContain("[Code Root Purge");
output.shouldNotContain("[Code Root Purge");
output.shouldNotContain("[Young Free CSet");
output.shouldNotContain("[Non-Young Free CSet");
output.shouldHaveExitValue(0);
pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
"-Xmx10M",
"-XX:+PrintGCDetails",
GCTest.class.getName());
output = new OutputAnalyzer(pb.start());
output.shouldContain("[Code Root Purge");
output.shouldNotContain("[Young Free CSet");
output.shouldNotContain("[Non-Young Free CSet");
output.shouldHaveExitValue(0);
pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
"-Xmx10M",
"-XX:+PrintGCDetails",
"-XX:+UnlockExperimentalVMOptions",
"-XX:G1LogLevel=finest",
GCTest.class.getName());
output = new OutputAnalyzer(pb.start());
output.shouldContain("[Code Root Purge");
output.shouldContain("[Young Free CSet");
output.shouldContain("[Non-Young Free CSet");
output.shouldHaveExitValue(0);
}
static class GCTest {