From: Quentin Perret <quentin.perret@arm.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Chris Redpath <chris.redpath@arm.com>,
Patrick Bellasi <patrick.bellasi@arm.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Thara Gopinath <thara.gopinath@linaro.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Todd Kjos <tkjos@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
Steve Muckle <smuckle@google.com>,
adharmap@codeaurora.org, Saravana Kannan <skannan@codeaurora.org>,
Pavan Kondeti <pkondeti@codeaurora.org>,
Juri Lelli <juri.lelli@redhat.com>,
Eduardo Valentin <edubezval@gmail.com>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
currojerez@riseup.net, Javi Merino <javi.merino@kernel.org>
Subject: Re: [PATCH v7 02/14] sched/cpufreq: Prepare schedutil for Energy Aware Scheduling
Date: Thu, 27 Sep 2018 13:17:49 +0100 [thread overview]
Message-ID: <20180927121749.urdqtayq6ll4k7qn@queper01-lin> (raw)
In-Reply-To: <CAJZ5v0gL+NurA8UcN5oweqwxfgS10HgO1Zjh_cod4_Sr5nWQHQ@mail.gmail.com>
Hi Rafael,
Very sorry for the late reply ...
On Tuesday 18 Sep 2018 at 23:33:22 (+0200), Rafael J. Wysocki wrote:
[...]
> The new "type" argument should be documented.
>
> Also IMO using the special enum for it is quite confusing, because you
> ever only check one value from it directly. What would be wrong with
> using a plain "bool" instead?
So, this part of the code was originally proposed by Peter. I basically
took it from the following message (hence the Suggested-by) which was
fine by me:
https://lore.kernel.org/lkml/20180709120138.GQ2494@hirez.programming.kicks-ass.net/
Also, one of the things that has been mentioned during reviews was that
other clients (such as cpuidle, IIRC) could potentially be interested
in a 'global' cpu util value. And since those clients might have
different needs than EAS or sugov, they might need a new entry in the
enum.
So that's probably the main argument for the enum, it is easy to extend.
[...]
> > +static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
> > +{
> > + struct rq *rq = cpu_rq(sg_cpu->cpu);
> > + unsigned long util = cpu_util_cfs(rq);
> > +
> > + sg_cpu->max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu);
> > + sg_cpu->bw_dl = cpu_bw_dl(rq);
> > +
> > + return schedutil_freq_util(sg_cpu->cpu, util, FREQUENCY_UTIL);
>
> If you add a "max" argument to schedutil_freq_util(), you can avoid
> the second (and arguably redundant) evaluation of
> arch_scale_cpu_capacity() in there.
OK
[...]
> > +enum schedutil_type {
> > + FREQUENCY_UTIL,
> > + ENERGY_UTIL,
> > +};
>
> As I said above, I would just use "bool" instead of this new enum (it
> has two values too) or the new type needs to be documented.
As I said above, the enum has the good side of being easier to extend.
So, if we care about that, I guess I'd rather add a doc for the new
type.
> > +
> > #ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
> > +unsigned long schedutil_freq_util(int cpu, unsigned long util_cfs,
> > + enum schedutil_type type);
> > +
> > static inline unsigned long cpu_bw_dl(struct rq *rq)
> > {
> > return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
> > @@ -2199,6 +2207,12 @@ static inline unsigned long cpu_util_rt(struct rq *rq)
> > {
> > return READ_ONCE(rq->avg_rt.util_avg);
> > }
> > +#else /* CONFIG_CPU_FREQ_GOV_SCHEDUTIL */
> > +static inline unsigned long schedutil_freq_util(int cpu, unsigned long util,
> > + enum schedutil_type type)
> > +{
> > + return util;
> > +}
> > #endif
>
> And I would add a wrapper around schedutil_freq_util(), called say
> schedutil_energy_util(), that would pass a specific value as the
> "type".
OK, that's fine by me.
Other than that, do you think these changes could be done later ? Or do
you see that as mandatory before the patches can be picked up ?
Thanks,
Quentin
next prev parent reply other threads:[~2018-09-27 12:18 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-12 9:12 [PATCH v7 00/14] Energy Aware Scheduling Quentin Perret
2018-09-12 9:12 ` [PATCH v7 01/14] sched: Relocate arch_scale_cpu_capacity Quentin Perret
2018-09-12 9:12 ` [PATCH v7 02/14] sched/cpufreq: Prepare schedutil for Energy Aware Scheduling Quentin Perret
2018-09-12 14:56 ` Vincent Guittot
2018-09-18 21:33 ` Rafael J. Wysocki
2018-09-27 12:17 ` Quentin Perret [this message]
2018-09-28 8:23 ` Rafael J. Wysocki
2018-09-28 8:35 ` Quentin Perret
2018-09-28 8:35 ` Rafael J. Wysocki
2018-09-12 9:12 ` [PATCH v7 03/14] PM: Introduce an Energy Model management framework Quentin Perret
2018-10-02 12:25 ` Peter Zijlstra
2018-10-02 12:54 ` Quentin Perret
2018-10-02 13:50 ` Peter Zijlstra
2018-10-02 12:30 ` Peter Zijlstra
2018-10-02 12:51 ` Quentin Perret
2018-10-02 13:48 ` Peter Zijlstra
2018-10-02 14:05 ` Quentin Perret
2018-10-02 14:29 ` Peter Zijlstra
2018-10-02 14:40 ` Quentin Perret
2018-10-02 19:12 ` Andrea Parri
2018-10-03 7:48 ` Quentin Perret
2018-09-12 9:12 ` [PATCH v7 04/14] PM / EM: Expose the Energy Model in sysfs Quentin Perret
2018-09-12 9:13 ` [PATCH v7 05/14] sched: Introduce a sched_feat for Energy Aware Scheduling Quentin Perret
2018-10-02 12:34 ` Peter Zijlstra
2018-10-02 13:08 ` Quentin Perret
2018-10-03 16:24 ` Peter Zijlstra
2018-10-04 9:57 ` Quentin Perret
2018-09-12 9:13 ` [PATCH v7 06/14] sched/topology: Reference the Energy Model of CPUs when available Quentin Perret
2018-10-02 12:36 ` Peter Zijlstra
2018-10-02 13:16 ` Quentin Perret
2018-09-12 9:13 ` [PATCH v7 07/14] sched/topology: Lowest CPU asymmetry sched_domain level pointer Quentin Perret
2018-09-12 9:13 ` [PATCH v7 08/14] sched/topology: Disable EAS on inappropriate platforms Quentin Perret
2018-10-03 16:27 ` Peter Zijlstra
2018-10-04 9:10 ` Quentin Perret
2018-10-04 9:38 ` Peter Zijlstra
2018-10-04 9:45 ` Quentin Perret
2018-09-12 9:13 ` [PATCH v7 09/14] sched/fair: Clean-up update_sg_lb_stats parameters Quentin Perret
2018-09-12 9:13 ` [PATCH v7 10/14] sched: Add over-utilization/tipping point indicator Quentin Perret
2018-09-12 9:13 ` [PATCH v7 11/14] sched/fair: Introduce an energy estimation helper function Quentin Perret
2018-10-04 8:34 ` Peter Zijlstra
2018-10-04 9:02 ` Quentin Perret
2018-09-12 9:13 ` [PATCH v7 12/14] sched/fair: Select an energy-efficient CPU on task wake-up Quentin Perret
2018-10-04 9:44 ` Peter Zijlstra
2018-10-04 10:27 ` Quentin Perret
2018-10-04 10:41 ` Peter Zijlstra
2018-10-04 10:55 ` Quentin Perret
2018-10-04 12:18 ` Peter Zijlstra
2018-09-12 9:13 ` [PATCH v7 13/14] sched/topology: Make Energy Aware Scheduling depend on schedutil Quentin Perret
2018-10-04 10:50 ` Peter Zijlstra
2018-10-04 11:58 ` Quentin Perret
2018-09-12 9:13 ` [PATCH v7 14/14] OPTIONAL: cpufreq: dt: Register an Energy Model Quentin Perret
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