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Issue 773312 link

Starred by 1 user
Status: WontFix
Owner: ----
Closed: Oct 2017
Cc:
bunge...@chromium.org
hnakashima@chromium.org
drott@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 2
Type: Bug



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Performance regression from FreeType roll

Project Member Reported by npm@chromium.org, Oct 10 2017 
Checkout PDFium commit 59454e1d00d37e9ec6b9341605d1e181e8dbec80. Use the testing/tools/safetynet_compare.py script (modifying so it does not gclient sync on current repo) to compare the performance of newer FreeType versions with respect to 7e50824288fac5a36c2938fdb3e1c949ea53f982 (the older FreeType commit). Test cases used: testing/corpus folder from PDFium.

Results:
With our new FreeType version (ae7dc1f): 84 regressions, 1 improvement from 708 testcases.

Did a bisect and found that these commits are the cause: https://chromium.googlesource.com/chromium/src/third_party/freetype2.git/+log/e28550a..d52dd7f.

Proof:
Commit d52dd7f (last bad commit): 84 regressions, 1 improvement from 708 testcases.
Commit d813b5d (one commit before first bad commit): 0 regressions, 0 improivements from 708 testcases.

So from these numbers it seems that switching to use the Adobe engine has slowed down FreeType? Do we know the reasoning behind that change?

Comment 1 by bunge...@chromium.org, Oct 10 2017 

So FreeType's old Type1 hinter was known for needing.... quality improvements. This was the target of a Google Summer of Code project which started here http://lists.nongnu.org/archive/html/freetype-devel/2017-03/msg00029.html . Effectively, FreeType is now using the Adobe CFF hinter instead of the old Type1 hinter for Type1 fonts, and I imagine that this is much slower (though hopefully has much better quality). If you can check that only Type1 fonts are slower, then this is probably expected. If other fonts (like CFF fonts) are slower as well, that may be worth investigating further.

The freetype-devel mailing list is also rather active and letting them know about this (especially if you can provide details on exactly which fonts, how FreeType is being called, the perf numbers, and any tracing hotspots) I'm sure there would be some interest, though they may not be able to do much about it. The new hinter is a lot better, but it also does more work.

Comment 2 by npm@chromium.org, Oct 10 2017

Status: WontFix (was: Untriaged)
Oh ok, thanks for the clarification. In that case, I hope the rendering improvements outweigh the performance costs. Marking WontFix for now.
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