On Mon, May 9, 2016 at 11:20 PM, Steve Muckle <steve.muc...@linaro.org> wrote:
> The rate limit timestamp (last_freq_update_time) is currently advanced
> anytime schedutil re-evaluates the policy regardless of whether the CPU
> frequency is changed or not. This means that utilization updates which
> have no effect can cause much more significant utilization updates
> (which require a large increase or decrease in CPU frequency) to be
> delayed due to rate limiting.
>
> Instead only update the rate limiting timstamp when the requested
> target-supported frequency changes. The rate limit will now apply to
> the rate of CPU frequency changes rather than the rate of
> re-evaluations of the policy frequency.
>
> Signed-off-by: Steve Muckle <smuc...@linaro.org>
I'm sort of divided here to be honest.
> ---
> kernel/sched/cpufreq_schedutil.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/sched/cpufreq_schedutil.c
> b/kernel/sched/cpufreq_schedutil.c
> index e185075fcb5c..4d2907c8a142 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -117,12 +117,11 @@ static void sugov_update_commit(struct sugov_cpu
> *sg_cpu, int cpu, u64 time,
> struct sugov_policy *sg_policy = sg_cpu->sg_policy;
> struct cpufreq_policy *policy = sg_policy->policy;
>
> - sg_policy->last_freq_update_time = time;
> -
> if (sg_policy->next_freq == next_freq) {
> trace_cpu_frequency(policy->cur, cpu);
You should at least rate limit the trace_cpu_frequency() thing here if
you don't want to advance the last update time I think, or you may
easily end up with the trace buffer flooded by irrelevant stuff.
> return;
> }
> + sg_policy->last_freq_update_time = time;
> sg_policy->next_freq = next_freq;
>
> if (sugov_queue_remote_callback(sg_policy, cpu))
> --
> 2.4.10
>
