Re: [PATCH v2] cpufreq: schedutil: Trace frequency only if it has changed

Viresh Kumar
2017-03-23T04:32:18Z

On 22-03-17, 18:32, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> sugov_update_commit() calls trace_cpu_frequency() to record the
> current CPU frequency if it has not changed in the fast switch case
> to prevent utilities from getting confused (they may report that the
> CPU is idle if the frequency has not been recorded for too long, for
> example).
>
> However, that may cause the tracepoint to be triggered quite often
> for no real reason (if the frequency doesn't change, we will not
> modify the last update time stamp and governor computations may
> run again shortly when that happens), so don't do that (arguably, it
> is done to work around a utilities bug anyway).
>
> That allows code duplication in sugov_update_commit() to be reduced
> somewhat too.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> -> v2:
> Drop the trace_cpu_frequency() call in the sg_policy->next_freq == next_freq case.
>
> ---
> kernel/sched/cpufreq_schedutil.c | 16 +++++++---------
> 1 file changed, 7 insertions(+), 9 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

--
viresh