From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755569AbaIKMeq (ORCPT ); Thu, 11 Sep 2014 08:34:46 -0400 Received: from casper.infradead.org ([85.118.1.10]:55855 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755517AbaIKMeO (ORCPT ); Thu, 11 Sep 2014 08:34:14 -0400 Date: Thu, 11 Sep 2014 14:34:12 +0200 From: Peter Zijlstra To: Vincent Guittot Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, preeti@linux.vnet.ibm.com, linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org, 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 10/12] sched: get CPU's utilization statistic Message-ID: <20140911123412.GY3190@worktop.ger.corp.intel.com> References: <1409051215-16788-1-git-send-email-vincent.guittot@linaro.org> <1409051215-16788-11-git-send-email-vincent.guittot@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1409051215-16788-11-git-send-email-vincent.guittot@linaro.org> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 26, 2014 at 01:06:53PM +0200, Vincent Guittot wrote: > Monitor the utilization level of each group of each sched_domain level. The > utilization is the amount of cpu_capacity that is currently used on a CPU or > group of CPUs. We use the usage_load_avg to evaluate this utilization level. > In the special use case where the CPU is fully loaded by more than 1 task, > the activity level is set above the cpu_capacity in order to reflect the overload > of the CPU > > Signed-off-by: Vincent Guittot > --- > kernel/sched/fair.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 1fd2131..2f95d1c 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4126,6 +4126,11 @@ static unsigned long capacity_of(int cpu) > return cpu_rq(cpu)->cpu_capacity; > } > > +static unsigned long capacity_orig_of(int cpu) > +{ > + return cpu_rq(cpu)->cpu_capacity_orig; > +} > + > static unsigned long cpu_avg_load_per_task(int cpu) > { > struct rq *rq = cpu_rq(cpu); This hunk should probably go into patch 6. > @@ -4514,6 +4519,17 @@ static int select_idle_sibling(struct task_struct *p, int target) > return target; > } > > +static int get_cpu_utilization(int cpu) > +{ > + unsigned long usage = cpu_rq(cpu)->cfs.usage_load_avg; > + unsigned long capacity = capacity_of(cpu); > + > + if (usage >= SCHED_LOAD_SCALE) > + return capacity + 1; > + > + return (usage * capacity) >> SCHED_LOAD_SHIFT; > +} So if I understood patch 9 correct, your changelog is iffy. usage_load_avg should never get > 1 (of whatever unit), no matter how many tasks are on the rq. You can only maximally run all the time. Therefore I can only interpret the if (usage >= SCHED_LOAD_SCALE) as numerical error handling, nothing more. Also I'm not entirely sure I like the usage, utilization names/metrics. I would suggest to reverse them. Call the pure running number 'utilization' and this scaled with capacity 'usage' or so. > @@ -6188,7 +6206,6 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd > /* Now, start updating sd_lb_stats */ > sds->total_load += sgs->group_load; > sds->total_capacity += sgs->group_capacity; > - > sg = sg->next; > } while (sg != env->sd->groups); > I like that extra line of whitespace, it separates the body from the loop itself. From mboxrd@z Thu Jan 1 00:00:00 1970 From: peterz@infradead.org (Peter Zijlstra) Date: Thu, 11 Sep 2014 14:34:12 +0200 Subject: [PATCH v5 10/12] sched: get CPU's utilization statistic In-Reply-To: <1409051215-16788-11-git-send-email-vincent.guittot@linaro.org> References: <1409051215-16788-1-git-send-email-vincent.guittot@linaro.org> <1409051215-16788-11-git-send-email-vincent.guittot@linaro.org> Message-ID: <20140911123412.GY3190@worktop.ger.corp.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Aug 26, 2014 at 01:06:53PM +0200, Vincent Guittot wrote: > Monitor the utilization level of each group of each sched_domain level. The > utilization is the amount of cpu_capacity that is currently used on a CPU or > group of CPUs. We use the usage_load_avg to evaluate this utilization level. > In the special use case where the CPU is fully loaded by more than 1 task, > the activity level is set above the cpu_capacity in order to reflect the overload > of the CPU > > Signed-off-by: Vincent Guittot > --- > kernel/sched/fair.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 1fd2131..2f95d1c 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4126,6 +4126,11 @@ static unsigned long capacity_of(int cpu) > return cpu_rq(cpu)->cpu_capacity; > } > > +static unsigned long capacity_orig_of(int cpu) > +{ > + return cpu_rq(cpu)->cpu_capacity_orig; > +} > + > static unsigned long cpu_avg_load_per_task(int cpu) > { > struct rq *rq = cpu_rq(cpu); This hunk should probably go into patch 6. > @@ -4514,6 +4519,17 @@ static int select_idle_sibling(struct task_struct *p, int target) > return target; > } > > +static int get_cpu_utilization(int cpu) > +{ > + unsigned long usage = cpu_rq(cpu)->cfs.usage_load_avg; > + unsigned long capacity = capacity_of(cpu); > + > + if (usage >= SCHED_LOAD_SCALE) > + return capacity + 1; > + > + return (usage * capacity) >> SCHED_LOAD_SHIFT; > +} So if I understood patch 9 correct, your changelog is iffy. usage_load_avg should never get > 1 (of whatever unit), no matter how many tasks are on the rq. You can only maximally run all the time. Therefore I can only interpret the if (usage >= SCHED_LOAD_SCALE) as numerical error handling, nothing more. Also I'm not entirely sure I like the usage, utilization names/metrics. I would suggest to reverse them. Call the pure running number 'utilization' and this scaled with capacity 'usage' or so. > @@ -6188,7 +6206,6 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd > /* Now, start updating sd_lb_stats */ > sds->total_load += sgs->group_load; > sds->total_capacity += sgs->group_capacity; > - > sg = sg->next; > } while (sg != env->sd->groups); > I like that extra line of whitespace, it separates the body from the loop itself.