From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751902AbaH3RHx (ORCPT ); Sat, 30 Aug 2014 13:07:53 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:51655 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751585AbaH3RHv (ORCPT ); Sat, 30 Aug 2014 13:07:51 -0400 Message-ID: <540204DC.5090204@linux.vnet.ibm.com> Date: Sat, 30 Aug 2014 22:37:40 +0530 From: Preeti U Murthy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Vincent Guittot , peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org CC: riel@redhat.com, Morten.Rasmussen@arm.com, efault@gmx.de, nicolas.pitre@linaro.org, linaro-kernel@lists.linaro.org, daniel.lezcano@linaro.org, dietmar.eggemann@arm.com Subject: Re: [PATCH v5 04/12] sched: Allow all archs to set the capacity_orig References: <1409051215-16788-1-git-send-email-vincent.guittot@linaro.org> <1409051215-16788-5-git-send-email-vincent.guittot@linaro.org> In-Reply-To: <1409051215-16788-5-git-send-email-vincent.guittot@linaro.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14083017-0928-0000-0000-000004736867 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Vincent, On 08/26/2014 04:36 PM, Vincent Guittot wrote: > capacity_orig is only changed for system with a SMT sched_domain level in order I think I had asked this before, but why only capacity_orig? The capacity of a group is also being updated the same way. This patch fixes the capacity of a group to reflect the capacity of the heterogeneous CPUs in it, this capacity being both the full capacity of the group: capacity_orig and the capacity available for the fair tasks. So I feel in the subject as well as the changelog it would suffice to say 'capacity'. > to reflect the lower capacity of CPUs. Heterogenous system also have to reflect an > original capacity that is different from the default value. > > Create a more generic function arch_scale_cpu_capacity that can be also used by > non SMT platform to set capacity_orig. > > The weak behavior of arch_scale_cpu_capacity is the previous SMT one in order to > keep backward compatibility in the use of capacity_orig. > > arch_scale_smt_capacity and default_scale_smt_capacity have been removed as > they were not use elsewhere than in arch_scale_cpu_capacity. > > Signed-off-by: Vincent Guittot > --- > kernel/sched/fair.c | 25 ++++++------------------- > 1 file changed, 6 insertions(+), 19 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index b85e9f7..8176bda 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5705,19 +5705,12 @@ unsigned long __weak arch_scale_freq_capacity(struct sched_domain *sd, int cpu) > return default_scale_capacity(sd, cpu); > } > > -static unsigned long default_scale_smt_capacity(struct sched_domain *sd, int cpu) > +unsigned long __weak arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) > { > - unsigned long weight = sd->span_weight; > - unsigned long smt_gain = sd->smt_gain; > + if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1)) > + return sd->smt_gain / sd->span_weight; > > - smt_gain /= weight; > - > - return smt_gain; > -} > - > -unsigned long __weak arch_scale_smt_capacity(struct sched_domain *sd, int cpu) > -{ > - return default_scale_smt_capacity(sd, cpu); > + return SCHED_CAPACITY_SCALE; > } > > static unsigned long scale_rt_capacity(int cpu) > @@ -5756,18 +5749,12 @@ static unsigned long scale_rt_capacity(int cpu) > > static void update_cpu_capacity(struct sched_domain *sd, int cpu) > { > - unsigned long weight = sd->span_weight; > unsigned long capacity = SCHED_CAPACITY_SCALE; > struct sched_group *sdg = sd->groups; > > - if ((sd->flags & SD_SHARE_CPUCAPACITY) && weight > 1) { > - if (sched_feat(ARCH_CAPACITY)) Aren't you missing this check above? I understand that it is not crucial, but that would also mean removing ARCH_CAPACITY sched_feat altogether, wouldn't it? Regards Preeti U Murthy > - capacity *= arch_scale_smt_capacity(sd, cpu); > - else > - capacity *= default_scale_smt_capacity(sd, cpu); > + capacity *= arch_scale_cpu_capacity(sd, cpu); > > - capacity >>= SCHED_CAPACITY_SHIFT; > - } > + capacity >>= SCHED_CAPACITY_SHIFT; > > sdg->sgc->capacity_orig = capacity; >