Changeset 128804 in webkit

Timestamp:

Sep 17, 2012 2:11:04 PM (12 years ago)

Author:

tony@chromium.org

Message:

Make CSS.PrefixUsage histogram smaller to save memory
​https://bugs.webkit.org/show_bug.cgi?id=96941

Reviewed by Ojan Vafai.

Each bucket costs about 12 bytes. This reduces the size of the histogram
from 600 to 384, which will save about 2.5k per renderer and browser
process.

In the long run, we could probably generate a table in makeprop.pl that
only has the webkit prefix values to save even more memory (there are
194 properties that start with -webkit).

No new tests, just refactoring.

• css/CSSParser.cpp:

(WebCore::cssPropertyID):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• css/CSSParser.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2012-09-17  Tony Chang  <tony@chromium.org>
+
+        Make CSS.PrefixUsage histogram smaller to save memory
+        https://bugs.webkit.org/show_bug.cgi?id=96941
+
+        Reviewed by Ojan Vafai.
+
+        Each bucket costs about 12 bytes. This reduces the size of the histogram
+        from 600 to 384, which will save about 2.5k per renderer and browser
+        process.
+
+        In the long run, we could probably generate a table in makeprop.pl that
+        only has the webkit prefix values to save even more memory (there are
+        194 properties that start with -webkit).
+
+        No new tests, just refactoring.
+
+        * css/CSSParser.cpp:
+        (WebCore::cssPropertyID):
+
 2012-09-17  Rob Buis  <rbuis@rim.com>
 

trunk/Source/WebCore/css/CSSParser.cpp

@@ -10419 +10419 @@
     const CSSPropertyID propertyID = hashTableEntry ? static_cast<CSSPropertyID>(hashTableEntry->id) : CSSPropertyInvalid;
 
-    // 600 is comfortably larger than numCSSProperties to allow for growth
-    static const int CSSPropertyHistogramSize = 600;
-    COMPILE_ASSERT(CSSPropertyHistogramSize > numCSSProperties, number_of_css_properties_exceed_CSSPropertyHistogramSize);
-
-    if (hasPrefix(buffer, length, "-webkit-") && propertyID != CSSPropertyInvalid)
-        HistogramSupport::histogramEnumeration("CSS.PrefixUsage", max(1, propertyID - firstCSSProperty), CSSPropertyHistogramSize);
+    static const int cssPropertyHistogramSize = numCSSProperties;
+    if (hasPrefix(buffer, length, "-webkit-") && propertyID != CSSPropertyInvalid) {
+        int histogramValue = propertyID - firstCSSProperty;
+        ASSERT(0 <= histogramValue && histogramValue < cssPropertyHistogramSize);
+        HistogramSupport::histogramEnumeration("CSS.PrefixUsage", histogramValue, cssPropertyHistogramSize);
+    }
 
     return propertyID;