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Issue 676846 link

Starred by 2 users

Issue metadata

Status: WontFix
Owner:
Closed: Oct 2017
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Windows
Pri: 2
Type: Bug



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Performance recording doesn't catch all the function calls

Reported by ovkadu...@gmail.com, Dec 23 2016

Issue description

UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36

Steps to reproduce the problem:
1. Open devtools for devtools
2. Open a JS file in the Source tab
3. Start recording by timeline
4. Select some text and make click right 
5. Stop recording
6. Go to flame chart
7. Find the _contextMenu function.

For details check out the attached animated flame.gif file.

What is the expected behavior?
1) In the flame chart as well in the Event log (at the bottom) it should display all the functions called inside the _contextMenu function.
2) It should be consistent.  

What went wrong?
1) In fact only two functions are shown under the _contextMenu function. And on the animated gif file (flame.gif) you can see that there were more than 2 calls insed the _contextMenu.
2) Some functions are displayed at one point of time and are not displayed if recording the same case once again. Please check out the flame2.gif and take a look at the _contextMenu function. Now it displays only 1 function call inside itself. Not even 2 as it was in the previous recording.
Also I found a post on SO with the same question: http://stackoverflow.com/questions/37743294/chrome-timeline-does-not-show-all-calls-on-a-flame-chart

Did this work before? N/A 

Chrome version: 55.0.2883.87  Channel: stable
OS Version: 10.0
Flash Version: Shockwave Flash 24.0 r0
 
flame.gif
6.2 MB View Download
flame2.gif
1.8 MB View Download

Comment 1 by ovkadu...@gmail.com, Dec 24 2016

The version of Chrome I specified is not correct. The gifs were recorded for 57.0.2960.0 (Official Build) canary (64-bit)
Cc: paulir...@chromium.org
Owner: alph@chromium.org
Status: Assigned (was: Unconfirmed)

Comment 3 by alph@chromium.org, Oct 18 2017

Status: WontFix (was: Assigned)
It's not a bug. It is by design.

1. DevTools use sampling technique to collect CPU profile. It records only those stacks where the sample landed.
2. Due to stochastic nature of the sampling it cannot be 100% consistent.

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