Title: [281879] trunk/Source/WebCore
- Revision
- 281879
- Author
- [email protected]
- Date
- 2021-09-01 14:34:59 -0700 (Wed, 01 Sep 2021)
Log Message
Improve time precision when cross-origin isolated via COOP+COEP
https://bugs.webkit.org/show_bug.cgi?id=228137
<rdar://problem/81197138>
Reviewed by Ryosuke Niwa.
Increase the precision of our high precision time (used by performance.now()) from
1ms to 20us when cross-origin isolated via COOP=same-origin + COEP=require-corp.
Precision remains the same (1ms) when not cross-origin isolated.
This aligns our behavior with Firefox.
Note that Chrome provides higher precision (100us in general and 5us when
cross-origin-isolated).
* dom/ScriptExecutionContext.cpp:
(WebCore::ScriptExecutionContext::setCrossOriginMode):
* page/Performance.cpp:
(WebCore::Performance::reduceTimeResolution):
(WebCore::Performance::allowHighPrecisionTime):
* page/Performance.h:
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (281878 => 281879)
--- trunk/Source/WebCore/ChangeLog 2021-09-01 21:30:55 UTC (rev 281878)
+++ trunk/Source/WebCore/ChangeLog 2021-09-01 21:34:59 UTC (rev 281879)
@@ -1,3 +1,27 @@
+2021-09-01 Chris Dumez <[email protected]>
+
+ Improve time precision when cross-origin isolated via COOP+COEP
+ https://bugs.webkit.org/show_bug.cgi?id=228137
+ <rdar://problem/81197138>
+
+ Reviewed by Ryosuke Niwa.
+
+ Increase the precision of our high precision time (used by performance.now()) from
+ 1ms to 20us when cross-origin isolated via COOP=same-origin + COEP=require-corp.
+ Precision remains the same (1ms) when not cross-origin isolated.
+
+ This aligns our behavior with Firefox.
+
+ Note that Chrome provides higher precision (100us in general and 5us when
+ cross-origin-isolated).
+
+ * dom/ScriptExecutionContext.cpp:
+ (WebCore::ScriptExecutionContext::setCrossOriginMode):
+ * page/Performance.cpp:
+ (WebCore::Performance::reduceTimeResolution):
+ (WebCore::Performance::allowHighPrecisionTime):
+ * page/Performance.h:
+
2021-09-01 Ryosuke Niwa <[email protected]>
Eagerly resolve slot elements to simply the code in SlotAssignment
Modified: trunk/Source/WebCore/dom/ScriptExecutionContext.cpp (281878 => 281879)
--- trunk/Source/WebCore/dom/ScriptExecutionContext.cpp 2021-09-01 21:30:55 UTC (rev 281878)
+++ trunk/Source/WebCore/dom/ScriptExecutionContext.cpp 2021-09-01 21:34:59 UTC (rev 281879)
@@ -47,6 +47,7 @@
#include "MessagePort.h"
#include "Navigator.h"
#include "Page.h"
+#include "Performance.h"
#include "PublicURLManager.h"
#include "RejectedPromiseTracker.h"
#include "ResourceRequest.h"
@@ -628,6 +629,8 @@
void ScriptExecutionContext::setCrossOriginMode(CrossOriginMode crossOriginMode)
{
globalCrossOriginMode = crossOriginMode;
+ if (crossOriginMode == CrossOriginMode::Isolated)
+ Performance::allowHighPrecisionTime();
}
CrossOriginMode ScriptExecutionContext::crossOriginMode()
Modified: trunk/Source/WebCore/page/Performance.cpp (281878 => 281879)
--- trunk/Source/WebCore/page/Performance.cpp 2021-09-01 21:30:55 UTC (rev 281878)
+++ trunk/Source/WebCore/page/Performance.cpp 2021-09-01 21:34:59 UTC (rev 281879)
@@ -58,6 +58,9 @@
WTF_MAKE_ISO_ALLOCATED_IMPL(Performance);
+constexpr Seconds highTimePrecision { 20_us };
+static Seconds timePrecision { 1_ms };
+
Performance::Performance(ScriptExecutionContext* context, MonotonicTime timeOrigin)
: ContextDestructionObserver(context)
, m_resourceTimingBufferFullTimer(*this, &Performance::resourceTimingBufferFullTimerFired) // FIXME: Migrate this to the event loop as well. https://bugs.webkit.org/show_bug.cgi?id=229044
@@ -92,11 +95,16 @@
Seconds Performance::reduceTimeResolution(Seconds seconds)
{
- double resolution = (1000_us).seconds();
+ double resolution = timePrecision.seconds();
double reduced = std::floor(seconds.seconds() / resolution) * resolution;
return Seconds(reduced);
}
+void Performance::allowHighPrecisionTime()
+{
+ timePrecision = highTimePrecision;
+}
+
DOMHighResTimeStamp Performance::relativeTimeFromTimeOriginInReducedResolution(MonotonicTime timestamp) const
{
Seconds seconds = timestamp - m_timeOrigin;
Modified: trunk/Source/WebCore/page/Performance.h (281878 => 281879)
--- trunk/Source/WebCore/page/Performance.h 2021-09-01 21:30:55 UTC (rev 281878)
+++ trunk/Source/WebCore/page/Performance.h 2021-09-01 21:34:59 UTC (rev 281879)
@@ -106,6 +106,7 @@
void registerPerformanceObserver(PerformanceObserver&);
void unregisterPerformanceObserver(PerformanceObserver&);
+ static void allowHighPrecisionTime();
static Seconds reduceTimeResolution(Seconds);
DOMHighResTimeStamp relativeTimeFromTimeOriginInReducedResolution(MonotonicTime) const;
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