1862597 - Build profiles still have some spikes in their CPU use charts

Status: RESOLVED FIXED

(Testing :: Mozbase, defect, P3)

Description

[Florian Quèze [:florian]]

Example profile: https://share.firefox.dev/3Qpn2PU

When zooming on a spike (eg. https://share.firefox.dev/3Mqn4pK) we see:

• There's a sample that's much longer than expected
• There's a short ~50ms sample.
• In the tooltips, the "CPU Percent" value is 100% for both samples.
• User+nice+system has a smaller value than expected (total isn't 100%) in the first long sample, and much larger than expected (total is more than 400%) in the second shorter sample.

There's likely an issue in the order of these lines: https://searchfox.org/mozilla-central/rev/11d085b63cf74b35737d9c036be80434883dd3f6/testing/mozbase/mozsystemmonitor/mozsystemmonitor/resourcemonitor.py#139-143

I think we would need to take the timestamp right after (or before?) the call to psutil.cpu_times.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:gbrown, could you have a look please?

For more information, please visit BugBot documentation.

Comment 2

[Florian Quèze [:florian]]

Attachment: Bug 1862597 - in resourcemonitor.py, take the timestamps right after the call to psutil.cpu_times, r=jcristau.

Comment 3

[Florian Quèze [:florian]]

Attachment: Bug 1862597 - when generating a profile from resourcemonitor.py, ensure the CPU use values used to display the chart are never above 100%, r=jcristau.

Depends on D198259

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/bdb5fb154d34
in resourcemonitor.py, take the timestamps right after the call to psutil.cpu_times, r=jcristau.
https://hg.mozilla.org/integration/autoland/rev/82efe64cc658
when generating a profile from resourcemonitor.py, ensure the CPU use values used to display the chart are never above 100%, r=jcristau.

Comment 5

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/bdb5fb154d34
https://hg.mozilla.org/mozilla-central/rev/82efe64cc658