Changeset 150912 in webkit

Timestamp:

May 29, 2013 11:37:10 AM (11 years ago)

Author:

rniwa@webkit.org

Message:

Remove the size of DataVector in HTMLToken
​https://bugs.webkit.org/show_bug.cgi?id=116931

Reviewed by Sam Weinig.

Merge ​https://chromium.googlesource.com/chromium/blink/+/7977721e62c471bfa17b84d82cd5d8243a4eb9a9.

Shink HTMLToken by 1.5 kB

HTMLToken has an inline vector for buffering characters during tokenization. We
originally picked the inline capacity of this buffer somewhat arbitrarily. This
CL tunes the number based on a somewhat non-scientific browse of a number of
popular web sites.

I (abarth) instrumented content_shell to log the length of each complete DataVector. I
then browsed around a variety of web sites to collect data. The 99% percentile
of DataVector lengths was just shy of 250 characters. I rounded that up to 256
because powers of two are pretty. That means we'll malloc an external buffer
less than 1% of the time, which seems fine.

• html/parser/HTMLToken.h:

(HTMLToken):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• html/parser/HTMLToken.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-05-29  Ryosuke Niwa  <rniwa@webkit.org>
+
+        Remove the size of DataVector in HTMLToken
+        https://bugs.webkit.org/show_bug.cgi?id=116931
+
+        Reviewed by Sam Weinig.
+
+        Merge https://chromium.googlesource.com/chromium/blink/+/7977721e62c471bfa17b84d82cd5d8243a4eb9a9.
+
+        Shink HTMLToken by 1.5 kB
+
+        HTMLToken has an inline vector for buffering characters during tokenization. We
+        originally picked the inline capacity of this buffer somewhat arbitrarily. This
+        CL tunes the number based on a somewhat non-scientific browse of a number of
+        popular web sites.
+
+        I (abarth) instrumented content_shell to log the length of each complete DataVector. I
+        then browsed around a variety of web sites to collect data. The 99% percentile
+        of DataVector lengths was just shy of 250 characters. I rounded that up to 256
+        because powers of two are pretty. That means we'll malloc an external buffer
+        less than 1% of the time, which seems fine.
+
+        * html/parser/HTMLToken.h:
+        (HTMLToken):
+
 2013-05-29  Brent Fulgham  <bfulgham@apple.com>
 

trunk/Source/WebCore/html/parser/HTMLToken.h

@@ -91 +91 @@
     };
 
-    typedef WTF::Vector<Attribute, 10> AttributeList;
-    typedef WTF::Vector<UChar, 1024> DataVector;
+    typedef Vector<Attribute, 10> AttributeList;
+    typedef Vector<UChar, 256> DataVector;
 
     HTMLToken() { clear(); }