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[GC] Change behavior when reaching external allocation limit

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With the recent changes to the incremental marking API we can now kick off
incremental marking while respecting callback flags.

Performance neutral for smoothness.image_decoding_cases on N9 (read: does not
crash) as long as we synchronously process phantom callbacks
(kGCCallbackFlagForced).

OORT single run:
  "marksweep": {
    "count": 5,
    "pause_min": 7.5,
    "pause_max": 158.8,
    "pause_avg": 97.52000000000001,
    "pause_gt_10ms": 4
  }
  --- vs ---
  "marksweep": {
    "count": 5,
    "pause_min": 16.2,
    "pause_max": 22.1,
    "pause_avg": 19.32,
    "pause_gt_10ms": 5
  }

The number of actual full GCs varies. The improvement manifests in reduced
maximum and average pauses.

BUG=chromium:515795
LOG=N

Review URL: https://codereview.chromium.org/1271253002

Cr-Commit-Position: refs/heads/master@{#30028}
This commit is contained in:
mlippautz 2015-08-05 06:29:01 -07:00 committed by Commit bot
parent 5e52e66591
commit 1cb27bce67
2 changed files with 18 additions and 2 deletions
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16
src/api.cc
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@ -6884,8 +6884,20 @@ Local<Integer> v8::Integer::NewFromUnsigned(Isolate* isolate, uint32_t value) {
void Isolate::CollectAllGarbage(const char* gc_reason) {
reinterpret_cast<i::Isolate*>(this)->heap()->CollectAllGarbage(
i::Heap::kNoGCFlags, gc_reason, v8::kGCCallbackFlagForced);
i::Heap* heap = reinterpret_cast<i::Isolate*>(this)->heap();
if (heap->incremental_marking()->IsStopped()) {
heap->StartIncrementalMarking(i::Heap::kNoGCFlags, kGCCallbackFlagForced,
gc_reason);
}
// TODO(mlippautz): Compute the time slice for incremental marking based on
// memory pressure.
double deadline = heap->MonotonicallyIncreasingTimeInMs() +
i::FLAG_external_allocation_limit_incremental_time;
heap->AdvanceIncrementalMarking(0, deadline,
i::IncrementalMarking::StepActions(
i::IncrementalMarking::GC_VIA_STACK_GUARD,
i::IncrementalMarking::FORCE_MARKING,
i::IncrementalMarking::FORCE_COMPLETION));
}

4
src/flag-definitions.h
View File

@ -810,6 +810,10 @@ DEFINE_BOOL(manual_evacuation_candidates_selection, false,
"Test mode only flag. It allows an unit test to select evacuation "
"candidates pages (requires --stress_compaction).")
// api.cc
DEFINE_INT(external_allocation_limit_incremental_time, 1,
"Time spent in incremental marking steps (in ms) once the external "
"allocation limit is reached")
//
// Dev shell flags