AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

Revert "cppgc: Minor fix in cppgc efficiency calculation"

Browse Source 
This reverts commit 543acf345a.

Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Mac%20-%20arm64%20-%20release/10365/overview

Original change's description:
> cppgc: Minor fix in cppgc efficiency calculation
>
> Efficiency calculation (freed bytes over GC duration) assumes that the
> duration of the GC is non zero. However, if the clock resolution is
> not small enough and the entire GC is very short, the timed value
> appears to be zero. This leads to NaN values showing in metrics and
> CHECKs failing. This CL fixes the issue.
>
> Bug: chromium:1338256
> Change-Id: I1dbc52072fcde3411aa38fa0c11da25afd107ca8
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3714356
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Commit-Queue: Nikolaos Papaspyrou <nikolaos@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#81329}

Bug: chromium:1338256
Change-Id: Ie9a23651494fc28a11bb59485a9812ee1a7cff48
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3721697
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Owners-Override: Nico Hartmann <nicohartmann@chromium.org>
Auto-Submit: Nico Hartmann <nicohartmann@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#81331}
This commit is contained in:
Nico Hartmann 2022-06-23 14:26:06 +00:00 committed by V8 LUCI CQ
parent 4c81827c8d
commit da12b9ac0b
2 changed files with 5 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
src/heap/cppgc/stats-collector.cc
View File

@ -160,10 +160,6 @@ double StatsCollector::GetRecentAllocationSpeedInBytesPerMs() const {
namespace {
int64_t SumPhases(const MetricRecorder::GCCycle::Phases& phases) {
DCHECK_LE(0, phases.mark_duration_us);
DCHECK_LE(0, phases.weak_duration_us);
DCHECK_LE(0, phases.compact_duration_us);
DCHECK_LE(0, phases.sweep_duration_us);
return phases.mark_duration_us + phases.weak_duration_us +
phases.compact_duration_us + phases.sweep_duration_us;
}
@ -219,23 +215,11 @@ MetricRecorder::GCCycle GetCycleEventForMetricRecorder(
static_cast<double>(event.objects.after_bytes) /
event.objects.before_bytes;
// Efficiency:
if (event.objects.freed_bytes == 0) {
event.efficiency_in_bytes_per_us = 0;
event.main_thread_efficiency_in_bytes_per_us = 0;
} else {
const int64_t sum_total = SumPhases(event.total);
const int64_t sum_main_thread = SumPhases(event.main_thread);
// The following check could be violated if the clock resolution is not
// small enough and the entire GC was very short, so the timed value was
// zero. See crbug.com/1338256. In this case, we expect that there won't be
// any freed bytes, so we will not be in this branch. If however the CHECK
// fails, we will need to provide an arbitrary value for efficiency here.
CHECK_NE(0, sum_main_thread);
event.efficiency_in_bytes_per_us =
static_cast<double>(event.objects.freed_bytes) / sum_total;
event.main_thread_efficiency_in_bytes_per_us =
static_cast<double>(event.objects.freed_bytes) / sum_main_thread;
}
event.efficiency_in_bytes_per_us =
static_cast<double>(event.objects.freed_bytes) / SumPhases(event.total);
event.main_thread_efficiency_in_bytes_per_us =
static_cast<double>(event.objects.freed_bytes) /
SumPhases(event.main_thread);
return event;
}

12
test/unittests/heap/cppgc/metric-recorder-unittest.cc
View File

@ -55,14 +55,6 @@ class MetricRecorderTest : public testing::TestWithHeap {
GarbageCollector::Config::CollectionType::kMajor,
GarbageCollector::Config::IsForcedGC::kNotForced);
}
void WaitGC(StatsCollector::ScopeId scope_id) {
// This ensures that the scope contains a non zero value.
StatsCollector::EnabledScope scope(stats, scope_id);
v8::base::TimeTicks time = v8::base::TimeTicks::Now();
while (time == v8::base::TimeTicks::Now()) {
// Force time to progress before destroying scope.
}
}
void EndGC(size_t marked_bytes) {
stats->NotifyMarkingCompleted(marked_bytes);
stats->NotifySweepingCompleted();
@ -289,11 +281,9 @@ TEST_F(MetricRecorderTest, CycleEndHistogramReportsCorrectValues) {
TEST_F(MetricRecorderTest, ObjectSizeMetricsNoAllocations) {
// Populate previous event.
StartGC();
WaitGC(StatsCollector::kAtomicMark);
EndGC(1000);
// Populate current event.
StartGC();
WaitGC(StatsCollector::kAtomicMark);
EndGC(800);
EXPECT_EQ(1000u, MetricRecorderImpl::GCCycle_event.objects.before_bytes);
EXPECT_EQ(800u, MetricRecorderImpl::GCCycle_event.objects.after_bytes);
@ -306,11 +296,9 @@ TEST_F(MetricRecorderTest, ObjectSizeMetricsNoAllocations) {
TEST_F(MetricRecorderTest, ObjectSizeMetricsWithAllocations) {
// Populate previous event.
StartGC();
WaitGC(StatsCollector::kAtomicMark);
EndGC(1000);
// Populate current event.
StartGC();
WaitGC(StatsCollector::kAtomicMark);
stats->NotifyAllocation(300);
stats->NotifyAllocatedMemory(1400);
stats->NotifyFreedMemory(700);