All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=835886

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=8ba429eb0257df3a9846cd350405e1e2f2fb157305afe1302f18d900f706d570


Bot(s) for this bug's original alert(s):

android-nexus6
android-nexus7v2

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/178ed831c40000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/178ed831c40000

Enable presentation feedback on Android by penghuang@chromium.org
https://chromium.googlesource.com/chromium/src/+/526c5b418ce687ac202fe15b99c5276d3081163f

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

My CL will send a presentation feedback IPC per frame. It supposes to replace the  update VSync parameters IPC. But I think we don't send VSync IPC on Android, because browser process can get the VSync parameters from SurfaceFlinger directlly, right? So probably it is expected behavior.

Hi piman@, am I right?

It sounds plausible...
What can we do to mitigate this overhead?

I plan to fix the problem by only sending presentation feedback IPC to a client, if the client requests presentation feedback for a swapbuffer.

 Issue 835858  has been merged into this issue.

I have landed several CLs which should fix this regression, but since related N7 N6 perf bots has been removed. I cannot verify it.

 Issue 836510  has been merged into this issue.

 Issue 836508  has been merged into this issue.

 Issue 836507  has been merged into this issue.

 Issue 836506  has been merged into this issue.

 Issue 836505  has been merged into this issue.

FWIW: the bump in nexus5 hasn't gone down: https://chromeperf.appspot.com/report?sid=385c763e9c6ba32a1b6615535b79b6dd33b2a0f7f43e914774c94144efdf8de5&start_rev=548420&end_rev=556363

Would you mind linking to the mitigation changes, for posterity? Thanks!

https://chromium.googlesource.com/chromium/src/+/2a30e263ea03bb6323981faae6038950be59dd3c

https://chromium.googlesource.com/chromium/src/+/03a8bf360f3466e36e71a1daa09bfbaca90b1e56

Those changes add a flag in SwapBuffers to request presentation feedback and VSync. So on android, we will not send the presnetation feedback IPC and VSync IPC by default unless there is a client is requesting it.