Changeset 245958 in webkit

Timestamp:

May 31, 2019 4:03:14 AM (5 years ago)

Author:

ajuma@chromium.org

Message:

REGRESSION (r245396): Page load time performance regression
​https://bugs.webkit.org/show_bug.cgi?id=198382

Reviewed by Simon Fraser.

Delay the scheduling of a rendering update by 500ms when a new
IntersectionObserver target is added during page load. This addresses
a page load time regression from r245396, which immediately scheduled a
rendering update when a target is added. Note that even with this change,
if anything else triggers a rendering update before the 500ms delay expires,
intersection observations will be updated during that rendering update.

Covered by intersection-observer/initial-observation.html

• dom/Document.cpp:

(WebCore::Document::updateIntersectionObservations):
(WebCore::Document::scheduleInitialIntersectionObservationUpdate):

• dom/Document.h:
• page/IntersectionObserver.cpp:

(WebCore::IntersectionObserver::observe):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• dom/Document.cpp (modified) (4 diffs)
• dom/Document.h (modified) (2 diffs)
• page/IntersectionObserver.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-05-31  Ali Juma  <ajuma@chromium.org>
+
+        REGRESSION (r245396): Page load time performance regression
+        https://bugs.webkit.org/show_bug.cgi?id=198382
+
+        Reviewed by Simon Fraser.
+
+        Delay the scheduling of a rendering update by 500ms when a new
+        IntersectionObserver target is added during page load. This addresses
+        a page load time regression from r245396, which immediately scheduled a
+        rendering update when a target is added. Note that even with this change,
+        if anything else triggers a rendering update before the 500ms delay expires,
+        intersection observations will be updated during that rendering update.
+
+        Covered by intersection-observer/initial-observation.html 
+
+        * dom/Document.cpp:
+        (WebCore::Document::updateIntersectionObservations):
+        (WebCore::Document::scheduleInitialIntersectionObservationUpdate):
+        * dom/Document.h:
+        * page/IntersectionObserver.cpp:
+        (WebCore::IntersectionObserver::observe):
+
 2019-05-30  Zan Dobersek  <zdobersek@igalia.com>
 

trunk/Source/WebCore/dom/Document.cpp

@@ -353 +353 @@
 };
 
+#if ENABLE(INTERSECTION_OBSERVER)
+static const Seconds intersectionObserversInitialUpdateDelay { 500_ms };
+#endif
+
 // DOM Level 2 says (letters added):
 //
@@ -537 +541 @@
 #if ENABLE(INTERSECTION_OBSERVER)
     , m_intersectionObserversNotifyTimer(*this, &Document::notifyIntersectionObserversTimerFired)
+    , m_intersectionObserversInitialUpdateTimer(*this, &Document::scheduleRenderingUpdate)
 #endif
     , m_loadEventDelayTimer(*this, &Document::loadEventDelayTimerFired)
@@ -7417 +7422 @@
         return;
 
+    m_intersectionObserversInitialUpdateTimer.stop();
+
     bool needsLayout = frameView->layoutContext().isLayoutPending() || (renderView() && renderView()->needsLayout());
     if (needsLayout || hasPendingStyleRecalc())
@@ -7505 +7512 @@
     m_intersectionObserversWithPendingNotifications.clear();
 }
+
+void Document::scheduleInitialIntersectionObservationUpdate()
+{
+    if (m_readyState == Complete)
+        scheduleRenderingUpdate();
+    else if (!m_intersectionObserversInitialUpdateTimer.isActive())
+        m_intersectionObserversInitialUpdateTimer.startOneShot(intersectionObserversInitialUpdateDelay);
+}
 #endif
 

trunk/Source/WebCore/dom/Document.h

@@ -1388 +1388 @@
     unsigned numberOfIntersectionObservers() const { return m_intersectionObservers.size(); }
     void updateIntersectionObservations();
+    void scheduleInitialIntersectionObservationUpdate();
 #endif
 
@@ -1822 +1823 @@
     Vector<WeakPtr<IntersectionObserver>> m_intersectionObserversWithPendingNotifications;
     Timer m_intersectionObserversNotifyTimer;
+    Timer m_intersectionObserversInitialUpdateTimer;
 #endif
 

trunk/Source/WebCore/page/IntersectionObserver.cpp

@@ -159 +159 @@
     if (!hadObservationTargets)
         document->addIntersectionObserver(*this);
-    document->scheduleRenderingUpdate();
+    document->scheduleInitialIntersectionObservationUpdate();
 }