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Issue 830021 link

Starred by 1 user
Status: Assigned
Owner:
g...@chromium.org
EstimatedDays: ----
NextAction: ----
OS: Android
Pri: 3
Type: Task



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Investigate clang's new pass manager for Chrome on Android

Project Member Reported by g...@chromium.org, Apr 6 2018 
Clang has a "new" (actually becoming pretty mature, but...) pass manager that's said to give a nice performance boost, especially with AFDO-optimized binaries. Since we have AFDO by default on Chrome OS and Android, it's probably good to try it there.

To be clear, this is a change that we're going to be opted into eventually (though it's unclear when "eventually" is). If it gives us a free perf boost, though, it might be worth opting into earlier rather than later.

I'll use this bug to group pinpoints and such. If the numbers look promising enough to warrant the 160KB binary size regression the new pass manager brings, I'll write up a doc/put numbers into a nicer format/etc. and probably spin off a "turn it on" bug.
Project Member

Comment 4 by 42576172...@developer.gserviceaccount.com, Apr 6 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/129fccc4c40000
Project Member

Comment 6 by 42576172...@developer.gserviceaccount.com, Apr 7 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/1493f4a4c40000
Project Member

Comment 7 by 42576172...@developer.gserviceaccount.com, Apr 7 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/13bb2e48c40000
Project Member

Comment 8 by 42576172...@developer.gserviceaccount.com, Apr 7 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/13ff3424c40000
Project Member

Comment 10 by 42576172...@developer.gserviceaccount.com, Apr 10 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/105a47b4c40000
Project Member

Comment 13 by 42576172...@developer.gserviceaccount.com, Apr 12 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/16f13932c40000
Project Member

Comment 14 by 42576172...@developer.gserviceaccount.com, Apr 12 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/1446e4a2c40000
Project Member

Comment 17 by 42576172...@developer.gserviceaccount.com, Apr 13 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/16e6f5c2c40000
Project Member

Comment 18 by 42576172...@developer.gserviceaccount.com, Apr 13 2018 

📍 Job complete. See results below.
https://pinpoint-dot-chromeperf.appspot.com/job/15e79392c40000

Comment 19 by g...@chromium.org, Apr 16 2018 

Couldn't find much of a difference on Android. The above two pinpoints are Linux, and I'm going to try one more time with AFDO+Linux enabled. If that doesn't show promise, then I think this is something we'll just take when it lands on us.

May be interesting to see where the +160KB binary size comes from if we're not seeing much performance gain, too.

Comment 20 by g...@chromium.org, Apr 16 2018 

Looks like ld.lld only grew flags to trivially support the new PM in r329598, and our in-tree clang is sitting around r328xxx. Will wait until we have a lld >= r329598 to continue here.

Comment 21 by g...@chromium.org, Apr 26 2018

Status: Assigned (was: Untriaged)
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