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RESOLVED FIXED
23676
Speed up uses of reserveCapacity on new vectors by adding a new reserveInitialCapacity
https://bugs.webkit.org/show_bug.cgi?id=23676
Summary
Speed up uses of reserveCapacity on new vectors by adding a new reserveInitia...
Darin Adler
Reported
2009-02-01 18:11:45 PST
In the parser, memcpy showed up on a profile, copying zero bytes when setting the initial capacity on the vector of attributes. This made me realize we could and should special-case the initial capacity setting to do less work and be more inline. Patch forthcoming.
Attachments
patch
(20.72 KB, patch)
2009-02-01 18:27 PST
,
Darin Adler
hyatt
: review+
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proposed patch, testcase, etc.
Darin Adler
Comment 1
2009-02-01 18:27:16 PST
Created
attachment 27239
[details]
patch
Dave Hyatt
Comment 2
2009-02-01 20:17:39 PST
Comment on
attachment 27239
[details]
patch I see a couple of cases where inline capacity could have just been used instead of wasting an extra call on reserveCapacity or reserveInitialCapacity. For example: textBuffer.reserveInitialCapacity(cMaxSegmentSize); Could you go through these changes and look for any that just used a fixed size constant all the time and convert them to use inline capacity instead? I think that would make those cases more readable and help make the intent of reserveInitialCapacity more clear. r=me
Darin Adler
Comment 3
2009-02-02 08:55:31 PST
(In reply to
comment #2
)
> (From update of
attachment 27239
[details]
[review]) > I see a couple of cases where inline capacity could have just been used instead > of wasting an extra call on reserveCapacity or reserveInitialCapacity. For > example: > > textBuffer.reserveInitialCapacity(cMaxSegmentSize); > > Could you go through these changes and look for any that just used a fixed size > constant all the time and convert them to use inline capacity instead? I think > that would make those cases more readable and help make the intent of > reserveInitialCapacity more clear.
I don't think inline capacity is always better; I'll look at the individual cases, but note that inline capacity means that the buffer can't be transferred to another object. For example, if you're planning to use String::adopt then inline capacity won't work.
Darin Adler
Comment 4
2009-02-02 16:28:01 PST
http://trac.webkit.org/changeset/40501
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