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Issue 879711 link

Starred by 2 users
Status: Assigned
Owner:
█ jbrandmeyer@chromium.org
Last visit > 30 days ago
Cc:
chromeos-kahlee-core@google.com
Components:
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: 3
Type: Bug



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chrome://tracing CPU frequency inaccurate on AMD Chromebooks

Project Member Reported by jbrandmeyer@chromium.org, Aug 31 
Chrome Version: 70.0.3524.2
Chrome OS Version: 10988.0.2018_08_21_1522 (Test Build)
Chrome OS Platform: Grunt/Careena, prerelease hardware
Network info: GoogleGuest

chrome://tracing produces a trace that includes a section of Kernel traces.  The Kernel traces include C-States and Clock Frequency for each processor core.  The displayed clock frequencies correspond to values reported by /sys/devices/system/cpu/cpu{N}/cpufreq/cpuinfo_cur_freq.  

However, this file is not the actual clock frequency of the core, it corresponds to the frequency the kernel has selected by C-state.  The actual core clock frequency may be found in /sys/devices/system/cpu/cpu{N}/cpufreq/scaling_cur_freq



Where is the right place to fix this?

Comment 1 by jbrandmeyer@chromium.org, Aug 31

Owner: jbrandmeyer@chromium.org

Have traced part of the dataflow through

(chromium) CrOsTracingAgent::StartTracing() when the trace config's IsSystraceEnabled() is true.

Farther down the stack,

(chromiumos) platform2/debugd/src/helpers/systrace.sh is setting up the kernel ftrace event power:cpu_frequency for this information.

Comment 2 by slangley@chromium.org, Sep 25

Labels: -CrOSFilesCategory-Performance

Comment 3 by dgozman@chromium.org, Oct 31

Components: -Platform>DevTools>Performance>Tracing Speed>Tracing

Comment 4 by benhenry@google.com, Jan 11

Status: Assigned (was: Unconfirmed)
This issue has an owner, a component and a priority, but is still listed as untriaged or unconfirmed. By definition, this bug is triaged. Changing status to "assigned". Please reach out to me if you disagree with how I've done this.
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