Revert "Reduce number of allocations in AutoStopwatch"

This reverts commit 3476c1d60ec29c5497123194acd7a9310b1023d2.
This commit is contained in:
wolfbeast 2019-01-29 00:40:24 +01:00 committed by Roy Tam
commit dce38e8d76
4 changed files with 11 additions and 25 deletions

View file

@ -6566,7 +6566,7 @@ struct JS_PUBLIC_API(PerformanceGroup) {
uint64_t refCount_;
};
using PerformanceGroupVector = mozilla::Vector<RefPtr<js::PerformanceGroup>, 8, SystemAllocPolicy>;
using PerformanceGroupVector = mozilla::Vector<RefPtr<js::PerformanceGroup>, 0, SystemAllocPolicy>;
/**
* Commit any Performance Monitoring data.

View file

@ -136,9 +136,6 @@ PerformanceMonitoring::start()
bool
PerformanceMonitoring::commit()
{
// Maximum initialization size, in elements for the vector of groups.
static const size_t MAX_GROUPS_INIT_CAPACITY = 1024;
#if !defined(MOZ_HAVE_RDTSC)
// The AutoStopwatch is only executed if `MOZ_HAVE_RDTSC`.
return false;
@ -155,19 +152,12 @@ PerformanceMonitoring::commit()
return true;
}
// The move operation is generally constant time, unless `recentGroups_.length()` is very small, in which case it's
// fast anyway because it's small.
PerformanceGroupVector recentGroups(Move(recentGroups_));
recentGroups_ = PerformanceGroupVector(); // Reconstruct after `Move`.
PerformanceGroupVector recentGroups;
recentGroups_.swap(recentGroups);
bool success = true;
if (stopwatchCommitCallback) {
success = stopwatchCommitCallback(iteration_, recentGroups, stopwatchCommitClosure);
}
// Heuristic use: we expect to have roughly the same number of groups as in the previous iteration.
const size_t capacity = std::min(recentGroups.capacity(), MAX_GROUPS_INIT_CAPACITY);
success = recentGroups_.reserve(capacity) && success;
if (stopwatchCommitCallback)
success = stopwatchCommitCallback(iteration_, recentGroups, stopwatchCommitClosure);
// Reset immediately, to make sure that we're not hit by the end
// of a nested event loop (which would cause `commit` to be called
@ -237,7 +227,7 @@ AutoStopwatch::AutoStopwatch(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IM
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
JSCompartment* compartment = cx_->compartment();
if (MOZ_UNLIKELY(compartment->scheduledForDestruction))
if (compartment->scheduledForDestruction)
return;
JSRuntime* runtime = cx_->runtime();
@ -276,11 +266,11 @@ AutoStopwatch::~AutoStopwatch()
}
JSCompartment* compartment = cx_->compartment();
if (MOZ_UNLIKELY(compartment->scheduledForDestruction))
if (compartment->scheduledForDestruction)
return;
JSRuntime* runtime = cx_->runtime();
if (MOZ_UNLIKELY(iteration_ != runtime->performanceMonitoring.iteration())) {
if (iteration_ != runtime->performanceMonitoring.iteration()) {
// We have entered a nested event loop at some point.
// Any information we may have is obsolete.
return;

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@ -1310,12 +1310,8 @@ nsPerformanceStatsService::GetResources(uint64_t* userTime,
void
nsPerformanceStatsService::NotifyJankObservers(const mozilla::Vector<uint64_t>& aPreviousJankLevels) {
// The move operation is generally constant time, unless `mPendingAlerts.length()` is very small, in which case it's
// fast anyway.
GroupVector alerts(Move(mPendingAlerts));
mPendingAlerts = GroupVector(); // Reconstruct after `Move`.
GroupVector alerts;
mPendingAlerts.swap(alerts);
if (!mPendingAlertsCollector) {
// We are shutting down.
return;

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@ -19,7 +19,7 @@
class nsPerformanceGroup;
class nsPerformanceGroupDetails;
typedef mozilla::Vector<RefPtr<nsPerformanceGroup>, 8> GroupVector;
typedef mozilla::Vector<RefPtr<nsPerformanceGroup>> GroupVector;
/**
* A data structure for registering observers interested in