Changeset 121218 in webkit for trunk/Source/JavaScriptCore

Timestamp:

Jun 25, 2012, 7:53:39 PM (13 years ago)

Author:

[email protected]

Message:

JSC should try to make profiling deterministic because otherwise reproducing failures is
nearly impossible
​https://bugs.webkit.org/show_bug.cgi?id=89940

Rubber stamped by Gavin Barraclough.

This rolls out the part of ​http://trac.webkit.org/changeset/121215 that introduced randomness
into the system. Now, instead of randomizing the tier-up threshold, we always set it to an
artificially low (and statically predetermined!) value. This gives most of the benefit of
threshold randomization without actually making the system behave completely differently on
each invocation.

• bytecode/ExecutionCounter.cpp:

(JSC::ExecutionCounter::setThreshold):

• runtime/Options.cpp:

(Options):
(JSC::Options::initializeOptions):

• runtime/Options.h:

(Options):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• bytecode/ExecutionCounter.cpp (modified) (1 diff)
• runtime/Options.cpp (modified) (2 diffs)
• runtime/Options.h (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2012-06-25  Filip Pizlo  <[email protected]>
+
+        JSC should try to make profiling deterministic because otherwise reproducing failures is
+        nearly impossible
+        https://bugs.webkit.org/show_bug.cgi?id=89940
+
+        Rubber stamped by Gavin Barraclough.
+        
+        This rolls out the part of http://trac.webkit.org/changeset/121215 that introduced randomness
+        into the system. Now, instead of randomizing the tier-up threshold, we always set it to an
+        artificially low (and statically predetermined!) value. This gives most of the benefit of
+        threshold randomization without actually making the system behave completely differently on
+        each invocation.
+
+        * bytecode/ExecutionCounter.cpp:
+        (JSC::ExecutionCounter::setThreshold):
+        * runtime/Options.cpp:
+        (Options):
+        (JSC::Options::initializeOptions):
+        * runtime/Options.h:
+        (Options):
+
 2012-06-22  Filip Pizlo  <[email protected]>
 

trunk/Source/JavaScriptCore/bytecode/ExecutionCounter.cpp

@@ -145 +145 @@
     }
 
-    int32_t maxThreshold =
-        codeBlock->globalObject()->weakRandomInteger() % Options::maximumExecutionCountsBetweenCheckpoints;
+    int32_t maxThreshold;
+    if (Options::randomizeExecutionCountsBetweenCheckpoints)
+        maxThreshold = codeBlock->globalObject()->weakRandomInteger() % Options::maximumExecutionCountsBetweenCheckpoints;
+    else
+        maxThreshold = Options::maximumExecutionCountsBetweenCheckpoints;
     if (threshold > maxThreshold)
         threshold = maxThreshold;

trunk/Source/JavaScriptCore/runtime/Options.cpp

@@ -68 +68 @@
 int32_t executionCounterIncrementForReturn;
 
+bool randomizeExecutionCountsBetweenCheckpoints;
 int32_t maximumExecutionCountsBetweenCheckpoints;
 
@@ -191 +192 @@
     SET(executionCounterIncrementForReturn, 15);
     
+    SET(randomizeExecutionCountsBetweenCheckpoints, false);
     SET(maximumExecutionCountsBetweenCheckpoints, 1000);
 

trunk/Source/JavaScriptCore/runtime/Options.h

@@ -54 +54 @@
 extern int32_t executionCounterIncrementForReturn;
 
+extern bool randomizeExecutionCountsBetweenCheckpoints;
 extern int32_t maximumExecutionCountsBetweenCheckpoints;