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Issue 790891 link

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Issue metadata

Status: Fixed
Owner:
Closed: Aug 20
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 2
Type: Bug



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Tracing CPU slices overlapped

Project Member Reported by vovoy@chromium.org, Dec 1 2017

Issue description

Chrome Version: 62.0.3202.94 (Official Build) (64-bit)
OS: all

What steps will reproduce the problem?
(1) Load the attached file overlap.json on chrome://tracing
(2) The following CPU slices overlapped:
  Running: 3ms - 5ms
  Runnable: 2ms - 7ms

What is the expected result?
The CPU slices shall not overlap.

The cause of the issue is that the "wakeup" variable in buildPerThreadCpuSlicesFromCpuState_() was kept until the next for loop iteration.
(https://cs.chromium.org/chromium/src/third_party/catapult/tracing/tracing/extras/importer/linux_perf/ftrace_importer.html?rcl=3ebc2fd9fe647478531367a1a5168631b6f2014d&l=556 )

I think "wakeup" shall not be kept, or the runnable slice will be overlapped with the previous running slice. Is there any case that "wakeup" must be kept until next iteration?
 
overlap.json
1.5 KB View Download

Comment 1 by vovoy@chromium.org, Dec 1 2017

Attached screenshot for this issue.
overlapped.png
30.1 KB View Download
Project Member

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

The following revision refers to this bug:
  https://chromium.googlesource.com/catapult/+/51f8305b51e9db61812a736653fff2898094906a

commit 51f8305b51e9db61812a736653fff2898094906a
Author: Vovo Yang <vovoy@google.com>
Date: Fri Dec 15 02:55:23 2017

Fix tracing CPU slices overlapping

The "wakeup" variable shall not be kept until the next for iteration, or
the runnable slice will be overlapped with the previous running slice.

Bug:  chromium:790891 
Change-Id: I0a5c9ec01878249fb105f233727ec515a7a3d556
Reviewed-on: https://chromium-review.googlesource.com/816456
Reviewed-by: Ethan Kuefner <eakuefner@chromium.org>
Reviewed-by: Ben Hayden <benjhayden@chromium.org>
Commit-Queue: Vovo Yang <vovoy@chromium.org>

[modify] https://crrev.com/51f8305b51e9db61812a736653fff2898094906a/tracing/tracing/extras/importer/linux_perf/ftrace_importer.html
[modify] https://crrev.com/51f8305b51e9db61812a736653fff2898094906a/tracing/tracing/extras/importer/linux_perf/ftrace_importer_test.html

Owner: vovoy@chromium.org
Status: Fixed (was: Available)

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