On Thu, Mar 28, 2019 at 10:48 AM Quentin Perret <[email protected]> wrote:
>
> Hi Rafael,
>
> On Tuesday 26 Mar 2019 at 12:18:00 (+0100), Rafael J. Wysocki wrote:
> > @@ -13,6 +13,8 @@
> > #include <linux/sched/cpufreq.h>
> > #include <trace/events/power.h>
> >
> > +#define IOWAIT_BOOST_MIN (SCHED_CAPACITY_SCALE / 8)
> > +
> > struct sugov_tunables {
> > struct gov_attr_set attr_set;
> > unsigned int rate_limit_us;
> > @@ -51,7 +53,6 @@ struct sugov_cpu {
> > u64 last_update;
> >
> > unsigned long bw_dl;
> > - unsigned long min;
> > unsigned long max;
> >
> > /* The field below is for single-CPU policies only: */
> > @@ -303,7 +304,7 @@ static bool sugov_iowait_reset(struct sua
>
> The comment above this function needs updating I think.
>
> > if (delta_ns <= TICK_NSEC)
> > return false;
> >
> > - sg_cpu->iowait_boost = set_iowait_boost ? sg_cpu->min : 0;
> > + sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
> > sg_cpu->iowait_boost_pending = set_iowait_boost;
> >
> > return true;
> > @@ -349,7 +350,7 @@ static void sugov_iowait_boost(struct su
>
> Ditto.
I overlooked these two, thanks for pointing that out!
Will send an update momentarily.
> > }
> >
> > /* First wakeup after IO: start with minimum boost */
> > - sg_cpu->iowait_boost = sg_cpu->min;
> > + sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
> > }
> >
> > /**
> > @@ -389,7 +390,7 @@ static unsigned long sugov_iowait_apply(
> > * No boost pending; reduce the boost value.
> > */
> > sg_cpu->iowait_boost >>= 1;
> > - if (sg_cpu->iowait_boost < sg_cpu->min) {
> > + if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
> > sg_cpu->iowait_boost = 0;
> > return util;
> > }
> > @@ -826,9 +827,6 @@ static int sugov_start(struct cpufreq_po
> > memset(sg_cpu, 0, sizeof(*sg_cpu));
> > sg_cpu->cpu = cpu;
> > sg_cpu->sg_policy = sg_policy;
> > - sg_cpu->min =
> > - (SCHED_CAPACITY_SCALE * policy->cpuinfo.min_freq) /
> > - policy->cpuinfo.max_freq;
> > }
> >
> > for_each_cpu(cpu, policy->cpus) {
> >
>
> Other than that, I tried a backport of this on a Pixel 3 with Snapdragon
> 845 (which is relevant because it has tons of OPPs, so starting at 128
> makes it ramp up faster) to check the impact on power, but the only
> differences appeared to be in the noise margin, so it's all good :)
Cool. :-)
> Full test results available at [1]. Note that I did enable the iowait
> boost feature for these tests -- it is disabled by default on P3 ...
Thanks!
> ---
> [1] https://nbviewer.jupyter.org/gist/qperret/69c9bde13aad2d783689e78c9ba2d9bc
