Hi,
On 05/12/17 15:09, Patrick Bellasi wrote:
> Hi Juri,
>
[...]
> > static void sugov_get_util(unsigned long *util, unsigned long *max, int
> > cpu)
> > {
> > struct rq *rq = cpu_rq(cpu);
> > - unsigned long cfs_max;
> > + unsigned long dl_util = (rq->dl.running_bw * SCHED_CAPACITY_SCALE)
> > + >> BW_SHIFT;
>
> What about using a pair of getter methods (e.g. cpu_util_{cfs,dl}) to
> be defined in kernel/sched/sched.h?
>
> This would help to hide class-specific signals mangling from cpufreq.
> And here we can have something "more abstract" like:
>
> unsigned long util_cfs = cpu_util_cfs(rq);
> unsigned long util_dl = cpu_util_dl(rq);
LGTM. I'll cook something for next spin.
>
> >
> > - cfs_max = arch_scale_cpu_capacity(NULL, cpu);
> > + *max = arch_scale_cpu_capacity(NULL, cpu);
> >
> > - *util = min(rq->cfs.avg.util_avg, cfs_max);
> > - *max = cfs_max;
> > + /*
> > + * Ideally we would like to set util_dl as min/guaranteed freq and
> > + * util_cfs + util_dl as requested freq. However, cpufreq is not yet
> > + * ready for such an interface. So, we only do the latter for now.
> > + */
>
> Maybe I don't completely get the above comment, but to me it is not
> really required.
>
> When you say that "util_dl" should be set to a min/guaranteed freq
> are you not actually talking about a DL implementation detail?
>
> From the cpufreq standpoint instead, we should always set a capacity
> which can accommodate util_dl + util_cfs.
It's more for platforms which supports such combination of values for
frequency requests (CPPC like, AFAIU). The idea being that util_dl is
what the system has to always guarantee, but it could go up to the sum
if feasible.
>
> We don't care about the meaning of util_dl and we should always assume
> (by default) that the signal is properly updated by the scheduling
> class... which unfortunately does not always happen for CFS.
>
>
> > + *util = min(rq->cfs.avg.util_avg + dl_util, *max);
>
> With the above proposal, here also we will have:
>
> *util = min(util_cfs + util_dl, *max);
Looks cleaner.
Thanks,
- Juri
