cpufreq: schedutil: Trace frequency only if it has changed
authorRafael J. Wysocki <rafael.j.wysocki@intel.com>
Wed, 22 Mar 2017 17:32:47 +0000 (18:32 +0100)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Fri, 24 Mar 2017 01:57:22 +0000 (02:57 +0100)
commit38d4ea229d25d30be6bf41bcd6cd663a587866ca
treee42f08d1d926e1e41df166d863d132d75be24c5b
parentb7eaf1aab9f8bd2e49fceed77ebc66c1b5800718
cpufreq: schedutil: Trace frequency only if it has changed

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>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
kernel/sched/cpufreq_schedutil.c