RESOLVED FIXED Bug 78323
[chromium] Increase JPEG decoding performance some moar 
https://bugs.webkit.org/show_bug.cgi?id=78323
Summary [chromium] Increase JPEG decoding performance some moar
noel gordon
Reported 2012-02-09 20:47:09 PST
[chromium] Increase JPEG decoding performance some moar
Attachments
Patch (19.72 KB, patch)
2012-02-09 21:14 PST, noel gordon 		no flags
DetailsFormatted DiffDiff
tjbench.fast.r778.svn.diff (1.66 KB, text/plain)
2012-02-09 22:23 PST, noel gordon 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
noel gordon
Comment 1 2012-02-09 21:14:05 PST
Created attachment 126447 [details] Patch
noel gordon
Comment 2 2012-02-09 22:21:46 PST
r101286 increased JPEG decoding performance by ~2x for the chromium ports, and similarly for the webkit android port in r104472. I then looked for even more performance and the result is this patch. Created an corpus of 369 jpeg images, composed of 4:4:4, 4:2:2, 4:2:0 chroma sampled images in graysacle, cmyk, and rgb (the majority). Modified libjpeg-turbo tjbench.c to allow the selection of fast decoding via a command line option. Compiled tjbench under cygwin windows7 x86_64 on a T410 laptop and a Z600 desktop, and also on a MacPro x86_32. Modified tjbench svn.diff at libjpeb-turbo r778 attached.
noel gordon
Comment 3 2012-02-09 22:23:33 PST
Created attachment 126454 [details] tjbench.fast.r778.svn.diff
noel gordon
Comment 4 2012-02-09 22:25:03 PST
Ran "./tjbench image.jpg -bgrx" for each image in the corpus. tjbench continuously decodes the image for 5 seconds, then reports the decoding throughput (Mbyte/s). I then repeated the experiment with fast decoding. The results are tabulated and graphed in the following spreadsheet. https://docs.google.com/spreadsheet/ccc?key=0Asd5UUPIMYYsdFNyTW95YzFUazJtUUZYY25UM0lZQ2c The results suggest fast decoding provides a 9% speed improvement (avg) across all machines.
Adam Barth
Comment 5 2012-02-09 23:39:02 PST
Comment on attachment 126447 [details] Patch Looks reasonable assuming you've reviewed all the changed test results as reasonable.
noel gordon
Comment 6 2012-02-10 00:02:00 PST
I have reviewed, and I am satisfied with, the changed test results on win and mac chrome.
WebKit Review Bot
Comment 7 2012-02-10 02:46:27 PST
Comment on attachment 126447 [details] Patch Clearing flags on attachment: 126447 Committed r107389: <http://trac.webkit.org/changeset/107389>
WebKit Review Bot
Comment 8 2012-02-10 02:46:32 PST
All reviewed patches have been landed. Closing bug.
Pavel Podivilov
Comment 9 2012-02-10 09:15:19 PST
Broke ExtensionChromePrivateApiTest.DecodeJPEG downstream. http://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=browser_tests&tests=ExtensionChromePrivateApiTest.DecodeJPEG
noel gordon
Comment 10 2012-02-10 14:25:47 PST
ExtensionChromePrivateApiTest.DecodeJPEG compares image bytes, rebaseline it after the webkit roll.
noel gordon
Comment 11 2012-02-10 14:31:15 PST
Peter, Sami: don't know how you rebaseline android layout test results, but you'll need to when this change rolls into chrome android.
noel gordon
Comment 12 2012-02-19 23:01:50 PST
Desktop chrome rebaselines, bug 78454.
noel gordon
Comment 13 2012-05-11 02:13:55 PDT
Backed part of this out in bug 85772. We now only allow IFAST decodes on small screen devices (Chromium Android).
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