* cpufreq dir under /sys/devices/system/cpu/cpu* is not present for online=0 cpus
@ 2014-09-23 14:49 Ragu
2014-09-30 10:00 ` Viresh Kumar
0 siblings, 1 reply; 2+ messages in thread
From: Ragu @ 2014-09-23 14:49 UTC (permalink / raw)
To: cpufreq
I am learning android and finding that the cpufreq dir under
/sys/devices/system/cpu/cpu* is not present when online=0 for a cpu. Why are
we hiding those directory and its content when a cpu goes offline/power
collapse ?
Because of the above, the cpu usage is not very accurate from some tools
which reads data from sysfs.
Thanks,
Ragu
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: cpufreq dir under /sys/devices/system/cpu/cpu* is not present for online=0 cpus
2014-09-23 14:49 cpufreq dir under /sys/devices/system/cpu/cpu* is not present for online=0 cpus Ragu
@ 2014-09-30 10:00 ` Viresh Kumar
0 siblings, 0 replies; 2+ messages in thread
From: Viresh Kumar @ 2014-09-30 10:00 UTC (permalink / raw)
To: Ragu; +Cc: cpufreq@vger.kernel.org, Linux PM list
On Tue, Sep 23, 2014 at 8:19 PM, Ragu <raguramanmm@gmail.com> wrote:
> I am learning android and finding that the cpufreq dir under
> /sys/devices/system/cpu/cpu* is not present when online=0 for a cpu. Why are
> we hiding those directory and its content when a cpu goes offline/power
> collapse ?
>
> Because of the above, the cpu usage is not very accurate from some tools
> which reads data from sysfs.
These were removed because the CPU isn't online anymore and so we shouldn't
be able to change its frequency from userspace.
But probably this behavior can be changed to mark cpufreq directory and its
file as read-only in that case.
But that is some work to do..
^ permalink raw reply [flat|nested] 2+ messages in thread
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2014-09-23 14:49 cpufreq dir under /sys/devices/system/cpu/cpu* is not present for online=0 cpus Ragu
2014-09-30 10:00 ` Viresh Kumar
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