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Issue 701181 link

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Issue metadata

Status: Fixed
Owner:
not on Chrome anymore
Closed: Mar 2017
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 3
Type: Bug



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Add UMA metrics for V-Sync smoothness and latency

Project Member Reported by stanisc@chromium.org, Mar 14 2017

Issue description

These metrics would be useful when testing impact of GPU V-sync on Windows (see Issue 467617).

V-sync latency is time from V-sync timestamp to when Scheduler receives or start handling it (as OnBeginFrame).

For V-sync smoothness for now we could look at one of existing BeginFrame UMA metrics. Ideally we'd want it to be expressed as something like coefficient of variance.

 
Status: Assigned (was: Untriaged)
Project Member

Comment 2 by bugdroid1@chromium.org, Mar 15 2017

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2b0182bca127df14fa7f3c8becb8ff682b3f1bd6

commit 2b0182bca127df14fa7f3c8becb8ff682b3f1bd6
Author: stanisc <stanisc@chromium.org>
Date: Wed Mar 15 20:31:43 2017

Add BeginFrameLatency UMA

The purpose of this UMA is to estimate v-sync latency i.e. the time
from hardware v-sync which is represented by BeginFrame timestamp
to the time BeginFrame is handled in Scheduler.

This metric will be useful to understand impact of GPU V-sync which
has been recently landed behind a feature switch.

BUG= 701181 
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2752573002
Cr-Commit-Position: refs/heads/master@{#457190}

[modify] https://crrev.com/2b0182bca127df14fa7f3c8becb8ff682b3f1bd6/cc/scheduler/compositor_timing_history.cc
[modify] https://crrev.com/2b0182bca127df14fa7f3c8becb8ff682b3f1bd6/cc/scheduler/compositor_timing_history.h
[modify] https://crrev.com/2b0182bca127df14fa7f3c8becb8ff682b3f1bd6/cc/scheduler/compositor_timing_history_unittest.cc
[modify] https://crrev.com/2b0182bca127df14fa7f3c8becb8ff682b3f1bd6/cc/scheduler/scheduler.cc
[modify] https://crrev.com/2b0182bca127df14fa7f3c8becb8ff682b3f1bd6/tools/metrics/histograms/histograms.xml

Project Member

Comment 3 by bugdroid1@chromium.org, Mar 17 2017

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0828f5b83f4835d9772dab5bd0bea6d8d9704737

commit 0828f5b83f4835d9772dab5bd0bea6d8d9704737
Author: stanisc <stanisc@chromium.org>
Date: Fri Mar 17 03:38:38 2017

Reimplement vsync latency UMA to be based on BeginImplFrame rather than BeginMainFrame

The previous fix that I submitted a couple of days ago mistakenly
hooked to a wrong Scheduler method which resulted in recording
latency for throttled BeginMainFrame call. BeginImplFrame is a much
better method to hook to.
I verified this locally by looking at chrome://histograms.
The browser side histogram now looks way cleaner than in the first
implementation.

BUG= 701181 
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2754943002
Cr-Commit-Position: refs/heads/master@{#457676}

[modify] https://crrev.com/0828f5b83f4835d9772dab5bd0bea6d8d9704737/cc/scheduler/compositor_timing_history.cc
[modify] https://crrev.com/0828f5b83f4835d9772dab5bd0bea6d8d9704737/cc/scheduler/compositor_timing_history.h
[modify] https://crrev.com/0828f5b83f4835d9772dab5bd0bea6d8d9704737/cc/scheduler/compositor_timing_history_unittest.cc
[modify] https://crrev.com/0828f5b83f4835d9772dab5bd0bea6d8d9704737/cc/scheduler/scheduler.cc
[modify] https://crrev.com/0828f5b83f4835d9772dab5bd0bea6d8d9704737/cc/scheduler/scheduler.h
[modify] https://crrev.com/0828f5b83f4835d9772dab5bd0bea6d8d9704737/tools/metrics/histograms/histograms.xml

Status: Fixed (was: Assigned)

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