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Bug 1897752 - Clean up layout telemetry. r=smaug

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This telemetry was trying to measure three things:

 * The time spent during style / layout in a tick. This is useful.
 * The times SetNeed{Style,Layout} flush have been called. This is not a
   particularly useful metric, there's not much to learn or change from
   it. Any call is basically free as long as they're consecutive /
   there's no flush in between.
 * The number of times layout / style has been flushed during a tick.
   This is more useful than the above but, similarly, there's not too
   much to be learned here. Number of flushes can be completely
   orthogonal to how expensive it has been.

It also had a number of flaws:

 * It is recorded per-PresShell, so we get multiple pings per tick.
 * Similarly, if a sub-frame dies before the tick, we just never report
   that time.

Instead, refactor it to make it simpler, and just record the first
metric reliably. This simplifies the code substantially, and I don't
think we're losing much.

The histograms are also expired. We might want to renew this, I'll file
a follow-up to either properly renew this if we plan to look at it, or
remove the code entirely from the tree.

Differential Revision: https://phabricator.services.mozilla.com/D210907
This commit is contained in:
Emilio Cobos Álvarez
2024-05-20 14:30:08 +00:00
parent 471a65dd6f
commit d4cd5b3261
7 changed files with 131 additions and 333 deletions
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217
layout/base/PresShell.cpp
View File

@@ -21,11 +21,11 @@
#include "mozilla/ArrayUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/AutoRestore.h"
#include "mozilla/CaretAssociationHint.h"
#include "mozilla/ContentIterator.h"
#include "mozilla/css/ImageLoader.h"
#include "mozilla/DisplayPortUtils.h"
#include "mozilla/layout/LayoutTelemetryTools.h"
#include "mozilla/dom/AncestorIterator.h"
#include "mozilla/dom/BrowserBridgeChild.h"
#include "mozilla/dom/BrowserChild.h"
@@ -4299,144 +4299,117 @@ void PresShell::DoFlushPendingNotifications(mozilla::ChangesToFlush aFlush) {
MOZ_DIAGNOSTIC_ASSERT(mIsDestroying || mViewManager);
MOZ_DIAGNOSTIC_ASSERT(mIsDestroying || mDocument->HasShellOrBFCacheEntry());
if (!isSafeToFlush) {
return;
}
// Make sure the view manager stays alive.
RefPtr<nsViewManager> viewManager = mViewManager;
bool didStyleFlush = false;
bool didLayoutFlush = false;
if (isSafeToFlush) {
// We need to make sure external resource documents are flushed too (for
// example, svg filters that reference a filter in an external document
// need the frames in the external document to be constructed for the
// filter to work). We only need external resources to be flushed when the
// main document is flushing >= FlushType::Frames, so we flush external
// resources here instead of Document::FlushPendingNotifications.
mDocument->FlushExternalResources(flushType);
// We need to make sure external resource documents are flushed too (for
// example, svg filters that reference a filter in an external document
// need the frames in the external document to be constructed for the
// filter to work). We only need external resources to be flushed when the
// main document is flushing >= FlushType::Frames, so we flush external
// resources here instead of Document::FlushPendingNotifications.
mDocument->FlushExternalResources(flushType);
// Force flushing of any pending content notifications that might have
// queued up while our event was pending. That will ensure that we don't
// construct frames for content right now that's still waiting to be
// notified on,
mDocument->FlushPendingNotifications(FlushType::ContentAndNotify);
// Force flushing of any pending content notifications that might have
// queued up while our event was pending. That will ensure that we don't
// construct frames for content right now that's still waiting to be
// notified on,
mDocument->FlushPendingNotifications(FlushType::ContentAndNotify);
mDocument->UpdateSVGUseElementShadowTrees();
mDocument->UpdateSVGUseElementShadowTrees();
// Process pending restyles, since any flush of the presshell wants
// up-to-date style data.
if (MOZ_LIKELY(!mIsDestroying)) {
viewManager->FlushDelayedResize();
mPresContext->FlushPendingMediaFeatureValuesChanged();
// Process pending restyles, since any flush of the presshell wants
// up-to-date style data.
if (MOZ_LIKELY(!mIsDestroying)) {
viewManager->FlushDelayedResize();
mPresContext->FlushPendingMediaFeatureValuesChanged();
}
if (MOZ_LIKELY(!mIsDestroying)) {
// Now that we have flushed media queries, update the rules before looking
// up @font-face / @counter-style / @font-feature-values rules.
StyleSet()->UpdateStylistIfNeeded();
// Flush any pending update of the user font set, since that could
// cause style changes (for updating ex/ch units, and to cause a
// reflow).
mDocument->FlushUserFontSet();
mPresContext->FlushCounterStyles();
mPresContext->FlushFontFeatureValues();
mPresContext->FlushFontPaletteValues();
// Flush any requested SMIL samples.
if (mDocument->HasAnimationController()) {
mDocument->GetAnimationController()->FlushResampleRequests();
}
}
// The FlushResampleRequests() above might have flushed style changes.
if (MOZ_LIKELY(!mIsDestroying)) {
if (aFlush.mFlushAnimations) {
mPresContext->EffectCompositor()->PostRestyleForThrottledAnimations();
mNeedThrottledAnimationFlush = false;
}
if (MOZ_LIKELY(!mIsDestroying)) {
// Now that we have flushed media queries, update the rules before looking
// up @font-face / @counter-style / @font-feature-values rules.
StyleSet()->UpdateStylistIfNeeded();
// Flush any pending update of the user font set, since that could
// cause style changes (for updating ex/ch units, and to cause a
// reflow).
mDocument->FlushUserFontSet();
mPresContext->FlushCounterStyles();
mPresContext->FlushFontFeatureValues();
mPresContext->FlushFontPaletteValues();
// Flush any requested SMIL samples.
if (mDocument->HasAnimationController()) {
mDocument->GetAnimationController()->FlushResampleRequests();
}
nsAutoScriptBlocker scriptBlocker;
Maybe<uint64_t> innerWindowID;
if (auto* window = mDocument->GetInnerWindow()) {
innerWindowID = Some(window->WindowID());
}
AutoProfilerStyleMarker tracingStyleFlush(std::move(mStyleCause),
innerWindowID);
PerfStats::AutoMetricRecording<PerfStats::Metric::Styling> autoRecording;
LAYOUT_TELEMETRY_RECORD(Restyle);
// The FlushResampleRequests() above might have flushed style changes.
if (MOZ_LIKELY(!mIsDestroying)) {
if (aFlush.mFlushAnimations) {
mPresContext->EffectCompositor()->PostRestyleForThrottledAnimations();
mNeedThrottledAnimationFlush = false;
}
mPresContext->RestyleManager()->ProcessPendingRestyles();
mNeedStyleFlush = false;
}
nsAutoScriptBlocker scriptBlocker;
Maybe<uint64_t> innerWindowID;
if (auto* window = mDocument->GetInnerWindow()) {
innerWindowID = Some(window->WindowID());
}
AutoProfilerStyleMarker tracingStyleFlush(std::move(mStyleCause),
innerWindowID);
PerfStats::AutoMetricRecording<PerfStats::Metric::Styling> autoRecording;
LAYOUT_TELEMETRY_RECORD_BASE(Restyle);
AssertFrameTreeIsSane(*this);
mPresContext->RestyleManager()->ProcessPendingRestyles();
mNeedStyleFlush = false;
}
AssertFrameTreeIsSane(*this);
didStyleFlush = true;
if (flushType >= (SuppressInterruptibleReflows()
? FlushType::Layout
: FlushType::InterruptibleLayout) &&
!mIsDestroying) {
didLayoutFlush = true;
if (DoFlushLayout(/* aInterruptible = */ flushType < FlushType::Layout)) {
if (flushType >= (SuppressInterruptibleReflows()
? FlushType::Layout
: FlushType::InterruptibleLayout) &&
!mIsDestroying) {
if (DoFlushLayout(/* aInterruptible = */ flushType < FlushType::Layout)) {
if (mContentToScrollTo) {
DoScrollContentIntoView();
if (mContentToScrollTo) {
DoScrollContentIntoView();
if (mContentToScrollTo) {
mContentToScrollTo->RemoveProperty(nsGkAtoms::scrolling);
mContentToScrollTo = nullptr;
}
mContentToScrollTo->RemoveProperty(nsGkAtoms::scrolling);
mContentToScrollTo = nullptr;
}
}
// FIXME(emilio): Maybe we should assert here but it's not 100% sure it'd
// hold right now, UnsuppressAndInvalidate and so on can run script...
if (MOZ_LIKELY(mDirtyRoots.IsEmpty())) {
mNeedLayoutFlush = false;
}
}
FlushPendingScrollResnap();
if (MOZ_LIKELY(!mIsDestroying)) {
// Try to trigger pending scroll-driven animations after we flush
// style and layout (if any). If we try to trigger them after flushing
// style but the frame tree is not ready, we will check them again after
// we flush layout because the requirement to trigger scroll-driven
// animations is that the associated scroll containers are ready (i.e. the
// scroll-timeline is active), and this depends on the readiness of the
// scrollable frame and the primary frame of the scroll container.
TriggerPendingScrollTimelineAnimations(mDocument);
}
if (flushType >= FlushType::Layout) {
if (!mIsDestroying) {
viewManager->UpdateWidgetGeometry();
}
// FIXME(emilio): Maybe we should assert here but it's not 100% sure it'd
// hold right now, UnsuppressAndInvalidate and so on can run script...
if (MOZ_LIKELY(mDirtyRoots.IsEmpty())) {
mNeedLayoutFlush = false;
}
}
// Update flush counters
if (didStyleFlush) {
mLayoutTelemetry.IncReqsPerFlush(FlushType::Style);
FlushPendingScrollResnap();
if (MOZ_LIKELY(!mIsDestroying)) {
// Try to trigger pending scroll-driven animations after we flush
// style and layout (if any). If we try to trigger them after flushing
// style but the frame tree is not ready, we will check them again after
// we flush layout because the requirement to trigger scroll-driven
// animations is that the associated scroll containers are ready (i.e. the
// scroll-timeline is active), and this depends on the readiness of the
// scrollable frame and the primary frame of the scroll container.
TriggerPendingScrollTimelineAnimations(mDocument);
}
if (didLayoutFlush) {
mLayoutTelemetry.IncReqsPerFlush(FlushType::Layout);
}
// Record telemetry for the number of requests per each flush type.
//
// Flushes happen as style or style+layout. This depends upon the `flushType`
// where flushType >= InterruptibleLayout means flush layout and flushType >=
// Style means flush style. We only report if didLayoutFlush or didStyleFlush
// is true because we care if a flush really did take place. (Flush is guarded
// by `isSafeToFlush == true`.)
if (flushType >= FlushType::InterruptibleLayout && didLayoutFlush) {
MOZ_ASSERT(didLayoutFlush == didStyleFlush);
mLayoutTelemetry.PingReqsPerFlushTelemetry(FlushType::Layout);
} else if (flushType >= FlushType::Style && didStyleFlush) {
MOZ_ASSERT(!didLayoutFlush);
mLayoutTelemetry.PingReqsPerFlushTelemetry(FlushType::Style);
if (flushType >= FlushType::Layout) {
if (!mIsDestroying) {
viewManager->UpdateWidgetGeometry();
}
}
}
@@ -9739,7 +9712,7 @@ bool PresShell::DoReflow(nsIFrame* target, bool aInterruptible,
AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING_RELEVANT_FOR_JS(
"Reflow", LAYOUT_Reflow, uri ? uri->GetSpecOrDefault() : "N/A"_ns);
LAYOUT_TELEMETRY_RECORD_BASE(Reflow);
LAYOUT_TELEMETRY_RECORD(Reflow);
PerfStats::AutoMetricRecording<PerfStats::Metric::Reflowing> autoRecording;
@@ -12096,10 +12069,6 @@ void PresShell::EndPaint() {
}
}
void PresShell::PingPerTickTelemetry(FlushType aFlushType) {
mLayoutTelemetry.PingPerTickTelemetry(aFlushType);
}
bool PresShell::GetZoomableByAPZ() const {
return mZoomConstraintsClient && mZoomConstraintsClient->GetAllowZoom();
}