Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 5 Feb 2024 13:11:24 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH] sched: cpufreq: Rename map_util_perf to apply_dvfs_headroom |
| |
On 05-02-24, 02:20, Qais Yousef wrote: > We are providing headroom for the utilization to grow until the next > decision point to pick the next frequency. Give the function a better > name and give it some documentation. It is not really mapping anything. > > Also move it to sched.h. This function relies on updating util signal > appropriately to give a headroom to grow. This is more of a scheduler > functionality than cpufreq. Move it to sched.h where all the other util > handling code belongs. > > Signed-off-by: Qais Yousef <qyousef@layalina.io> > --- > include/linux/sched/cpufreq.h | 5 ----- > kernel/sched/cpufreq_schedutil.c | 2 +- > kernel/sched/sched.h | 17 +++++++++++++++++ > 3 files changed, 18 insertions(+), 6 deletions(-) > > diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h > index bdd31ab93bc5..d01755d3142f 100644 > --- a/include/linux/sched/cpufreq.h > +++ b/include/linux/sched/cpufreq.h > @@ -28,11 +28,6 @@ static inline unsigned long map_util_freq(unsigned long util, > { > return freq * util / cap; > } > - > -static inline unsigned long map_util_perf(unsigned long util) > -{ > - return util + (util >> 2); > -} > #endif /* CONFIG_CPU_FREQ */ > > #endif /* _LINUX_SCHED_CPUFREQ_H */ > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index 95c3c097083e..abbd1ddb0359 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -179,7 +179,7 @@ unsigned long sugov_effective_cpu_perf(int cpu, unsigned long actual, > unsigned long max) > { > /* Add dvfs headroom to actual utilization */ > - actual = map_util_perf(actual); > + actual = apply_dvfs_headroom(actual); > /* Actually we don't need to target the max performance */ > if (actual < max) > max = actual; > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index e58a54bda77d..0da3425200b1 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -3002,6 +3002,23 @@ unsigned long sugov_effective_cpu_perf(int cpu, unsigned long actual, > unsigned long min, > unsigned long max); > > +/* > + * DVFS decision are made at discrete points. If CPU stays busy, the util will > + * continue to grow, which means it could need to run at a higher frequency > + * before the next decision point was reached. IOW, we can't follow the util as > + * it grows immediately, but there's a delay before we issue a request to go to > + * higher frequency. The headroom caters for this delay so the system continues > + * to run at adequate performance point. > + * > + * This function provides enough headroom to provide adequate performance > + * assuming the CPU continues to be busy. > + * > + * At the moment it is a constant multiplication with 1.25. > + */ > +static inline unsigned long apply_dvfs_headroom(unsigned long util) > +{ > + return util + (util >> 2); > +} > > /* > * Verify the fitness of task @p to run on @cpu taking into account the
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
-- viresh
| ![\](/images/icornerr.gif) |