Bug 38154

Summary: REGRESSION: after 56028 FastMalloc calls madvise too often
Product: WebKit Reporter: Stephanie Lewis <slewis>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: ggaren, slewis, webkit.review.bot
Priority: P2 Keywords: InRadar
Version: 528+ (Nightly build)   
Hardware: PC   
OS: OS X 10.5   
Attachments:
Description Flags
Change the recommit policy to commit entire spans at one time. ggaren: review+

Description Stephanie Lewis 2010-04-26 17:31:24 PDT 
<rdar://problem/7834433> REGRESSSION: 1.5% PLT regression due to 56028 (return memory quicker).  
        To save on madvise calls when recommitting memory recommit the entire chosen span and then carve the span
        instead of carving the span up and only committing the part that will be used immediately.
Comment 1 Stephanie Lewis 2010-04-26 17:43:09 PDT 
Created attachment 54354 [details]
Change the recommit policy to commit entire spans at one time.

Change the recommit policy to recommit entire spans at one time.
Comment 2 WebKit Review Bot 2010-04-26 17:45:41 PDT 
Attachment 54354 [details] did not pass style-queue:

Failed to run "['WebKitTools/Scripts/check-webkit-style', '--no-squash']" exit_code: 1
JavaScriptCore/wtf/FastMalloc.cpp:1688:  Weird number of spaces at line-start.  Are you using a 4-space indent?  [whitespace/indent] [3]
JavaScriptCore/wtf/FastMalloc.cpp:1694:  Weird number of spaces at line-start.  Are you using a 4-space indent?  [whitespace/indent] [3]
Total errors found: 2 in 2 files


If any of these errors are false positives, please file a bug against check-webkit-style.
Comment 3 Geoffrey Garen 2010-04-27 10:14:18 PDT 
Comment on attachment 54354 [details]
Change the recommit policy to commit entire spans at one time.

r=me

Any data on how much of an improvement this is?
Comment 4 Stephanie Lewis 2010-04-27 16:31:23 PDT 
Committed http://trac.webkit.org/changeset/58346.

This is about a .5% improvement.  The FastMalloc file has historically not conformed to style guidelines, and my changes matched the file's style.