Question on perf counter

Question on perf counter

[Mathew Li]

Hi All,

I have a piece of kernel code (actually some assembly functions) on
ARM-v8. I want to know how many cycles CPU is taking to execute them.
I believe I could use performance counter for this job. So are there
some APIs in kernel for performance counter for ARM-v8 which I could
make use of?

Thanks!
Matt

Question on perf counter

[Jean Pihet]

Matt,

On Wed, Jun 11, 2014 at 3:07 AM, Mathew Li <mathew.li100@gmail.com> wrote:
> Hi All,
>
> I have a piece of kernel code (actually some assembly functions) on
> ARM-v8. I want to know how many cycles CPU is taking to execute them.
> I believe I could use performance counter for this job. So are there
> some APIs in kernel for performance counter for ARM-v8 which I could
> make use of?

The kernel has the profiling tools for that.
Perf has a lot of features that you need to experiment with. Cf.
https://wiki.linaro.org/LEG/Engineering/TOOLS/tracing-and-profiling-tools
and https://wiki.yoctoproject.org/wiki/Tracing_and_Profiling for
detailed information and usage of perf, ftrace ...

Regards,
Jean

>
> Thanks!
> Matt
>
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