Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753368AbdGGD0D (ORCPT ); Thu, 6 Jul 2017 23:26:03 -0400 Received: from mail-oi0-f52.google.com ([209.85.218.52]:35645 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753322AbdGGD0C (ORCPT ); Thu, 6 Jul 2017 23:26:02 -0400 MIME-Version: 1.0 In-Reply-To: <20170705085905.6558-5-juri.lelli@arm.com> References: <20170705085905.6558-1-juri.lelli@arm.com> <20170705085905.6558-5-juri.lelli@arm.com> From: Joel Fernandes Date: Thu, 6 Jul 2017 20:26:00 -0700 Message-ID: Subject: Re: [RFC PATCH v1 4/8] sched/cpufreq_schedutil: split utilization signals To: Juri Lelli Cc: Peter Zijlstra , Ingo Molnar , "Rafael J. Wysocki" , Viresh Kumar , LKML , Linux PM , Thomas Gleixner , Vincent Guittot , Steven Rostedt , luca.abeni@santannapisa.it, claudio@evidence.eu.com, Tommaso Cucinotta , bristot@redhat.com, mathieu.poirier@linaro.org, Todd Kjos , Andres Oportus , Morten Rasmussen , Dietmar Eggemann , Patrick Bellasi , Ingo Molnar , "Rafael J . Wysocki" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3420 Lines: 83 Hi Juri, On Wed, Jul 5, 2017 at 1:59 AM, Juri Lelli wrote: > To be able to treat utilization signals of different scheduling classes > in different ways (e.g., CFS signal might be stale while DEADLINE signal > is never stale by design) we need to split sugov_cpu::util signal in two: > util_cfs and util_dl. > > This patch does that by also changing sugov_get_util() parameter list. > After this change, aggregation of the different signals has to be performed > by sugov_get_util() users (so that they can decide what to do with the > different signals). > > Suggested-by: Rafael J. Wysocki > Signed-off-by: Juri Lelli > Cc: Peter Zijlstra > Cc: Ingo Molnar > Cc: Rafael J. Wysocki > Cc: Viresh Kumar > Cc: Luca Abeni > Cc: Claudio Scordino > --- > Changes from RFCv0: > > - refactor aggregation of utilization in sugov_aggregate_util() > --- > kernel/sched/cpufreq_schedutil.c | 28 ++++++++++++++++------------ > 1 file changed, 16 insertions(+), 12 deletions(-) > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index ba6227625f24..e835fa886225 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -58,7 +58,8 @@ struct sugov_cpu { > u64 last_update; > > /* The fields below are only needed when sharing a policy. */ > - unsigned long util; > + unsigned long util_cfs; > + unsigned long util_dl; > unsigned long max; > unsigned int flags; > > @@ -154,20 +155,24 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy, > return cpufreq_driver_resolve_freq(policy, freq); > } > > -static void sugov_get_util(unsigned long *util, unsigned long *max) > +static void sugov_get_util(struct sugov_cpu *sg_cpu) > { > struct rq *rq = this_rq(); > - unsigned long dl_util = (rq->dl.running_bw * SCHED_CAPACITY_SCALE) > - >> BW_SHIFT; > > - *max = arch_scale_cpu_capacity(NULL, smp_processor_id()); > + sg_cpu->max = arch_scale_cpu_capacity(NULL, smp_processor_id()); > + sg_cpu->util_cfs = rq->cfs.avg.util_avg; > + sg_cpu->util_dl = (rq->dl.running_bw * SCHED_CAPACITY_SCALE) > + >> BW_SHIFT; > +} > > +static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu) > +{ > /* > * 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. > */ > - *util = min(rq->cfs.avg.util_avg + dl_util, *max); > + return min(sg_cpu->util_cfs + sg_cpu->util_dl, sg_cpu->max); > } I am wondering why the need for a separate aggregation API. To me, it looks like using sugov_get_util to set the sg_cpu util elements and then do the aggregation at the same time would have the same effect (without changing the existing parameter list). Is this to handle a future usecase where aggregation may need to be done differently? For all the user's of sugov_get_util, aggregation is done in the same way. Anyway if I missed something, sorry for the noise. thanks, -Joel