From: peterz@infradead.org (Peter Zijlstra)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v7 6/7] sched: replace capacity_factor by usage
Date: Thu, 9 Oct 2014 17:18:20 +0200 [thread overview]
Message-ID: <20141009151820.GX10832@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtCX687FkGgxLO7spfGvDxhDWeFDERLRZ-NakO2Jrpmnhw@mail.gmail.com>
On Thu, Oct 09, 2014 at 04:18:02PM +0200, Vincent Guittot wrote:
> On 9 October 2014 14:16, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Tue, Oct 07, 2014 at 02:13:36PM +0200, Vincent Guittot wrote:
> >> +static inline bool
> >> +group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs)
> >> {
> >> + if ((sgs->group_capacity * 100) >
> >> + (sgs->group_usage * env->sd->imbalance_pct))
> >> + return true;
> >
> > Why the imb_pct there? We're looking for 100% utilization, not 130 or
> > whatnot, right?
>
> Having exactly 100% is quite difficult because of various rounding.
> So i have added a margin/threshold to prevent any excessive change of the state.
> I have just to use the same margin/threshold than in other place in
> load balance.
>
Yet you failed to mention this anywhere. Also does it really matter?
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>,
Morten Rasmussen <Morten.Rasmussen@arm.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
LAK <linux-arm-kernel@lists.infradead.org>,
Rik van Riel <riel@redhat.com>, Mike Galbraith <efault@gmx.de>,
Nicolas Pitre <nicolas.pitre@linaro.org>,
"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Paul Turner <pjt@google.com>,
Benjamin Segall <bsegall@google.com>
Subject: Re: [PATCH v7 6/7] sched: replace capacity_factor by usage
Date: Thu, 9 Oct 2014 17:18:20 +0200 [thread overview]
Message-ID: <20141009151820.GX10832@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtCX687FkGgxLO7spfGvDxhDWeFDERLRZ-NakO2Jrpmnhw@mail.gmail.com>
On Thu, Oct 09, 2014 at 04:18:02PM +0200, Vincent Guittot wrote:
> On 9 October 2014 14:16, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Tue, Oct 07, 2014 at 02:13:36PM +0200, Vincent Guittot wrote:
> >> +static inline bool
> >> +group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs)
> >> {
> >> + if ((sgs->group_capacity * 100) >
> >> + (sgs->group_usage * env->sd->imbalance_pct))
> >> + return true;
> >
> > Why the imb_pct there? We're looking for 100% utilization, not 130 or
> > whatnot, right?
>
> Having exactly 100% is quite difficult because of various rounding.
> So i have added a margin/threshold to prevent any excessive change of the state.
> I have just to use the same margin/threshold than in other place in
> load balance.
>
Yet you failed to mention this anywhere. Also does it really matter?
next prev parent reply other threads:[~2014-10-09 15:18 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-07 12:13 [PATCH v7 0/7] sched: consolidation of cpu_capacity Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
2014-10-07 12:13 ` [PATCH v7 1/7] sched: add per rq cpu_capacity_orig Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
2014-10-07 12:13 ` [PATCH v7 2/7] sched: move cfs task on a CPU with higher capacity Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
2014-10-09 11:23 ` Peter Zijlstra
2014-10-09 11:23 ` Peter Zijlstra
2014-10-09 14:59 ` Vincent Guittot
2014-10-09 14:59 ` Vincent Guittot
2014-10-09 15:30 ` Peter Zijlstra
2014-10-09 15:30 ` Peter Zijlstra
2014-10-10 7:46 ` Vincent Guittot
2014-10-10 7:46 ` Vincent Guittot
2014-10-07 12:13 ` [PATCH v7 3/7] sched: add utilization_avg_contrib Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
2014-10-08 17:04 ` Dietmar Eggemann
2014-10-08 17:04 ` Dietmar Eggemann
2014-10-07 12:13 ` [PATCH 4/7] sched: Track group sched_entity usage contributions Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
2014-10-07 20:15 ` bsegall at google.com
2014-10-07 20:15 ` bsegall
2014-10-08 7:16 ` Vincent Guittot
2014-10-08 7:16 ` Vincent Guittot
2014-10-08 11:13 ` Morten Rasmussen
2014-10-08 11:13 ` Morten Rasmussen
2014-10-07 12:13 ` [PATCH v7 5/7] sched: get CPU's usage statistic Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
2014-10-09 11:36 ` Peter Zijlstra
2014-10-09 11:36 ` Peter Zijlstra
2014-10-09 13:57 ` Vincent Guittot
2014-10-09 13:57 ` Vincent Guittot
2014-10-09 15:12 ` Peter Zijlstra
2014-10-09 15:12 ` Peter Zijlstra
2014-10-10 14:38 ` Vincent Guittot
2014-10-10 14:38 ` Vincent Guittot
2014-10-07 12:13 ` [PATCH v7 6/7] sched: replace capacity_factor by usage Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
2014-10-09 12:16 ` Peter Zijlstra
2014-10-09 12:16 ` Peter Zijlstra
2014-10-09 14:18 ` Vincent Guittot
2014-10-09 14:18 ` Vincent Guittot
2014-10-09 15:18 ` Peter Zijlstra [this message]
2014-10-09 15:18 ` Peter Zijlstra
2014-10-10 7:17 ` Vincent Guittot
2014-10-10 7:17 ` Vincent Guittot
2014-10-10 7:18 ` Vincent Guittot
2014-10-10 7:18 ` Vincent Guittot
2014-11-23 1:03 ` Wanpeng Li
2014-11-23 1:03 ` Wanpeng Li
2014-11-24 10:16 ` Vincent Guittot
2014-11-24 10:16 ` Vincent Guittot
2014-10-09 14:16 ` Peter Zijlstra
2014-10-09 14:16 ` Peter Zijlstra
2014-10-09 14:28 ` Vincent Guittot
2014-10-09 14:28 ` Vincent Guittot
2014-10-09 14:58 ` Peter Zijlstra
2014-10-09 14:58 ` Peter Zijlstra
2014-10-21 7:38 ` Vincent Guittot
2014-10-21 7:38 ` Vincent Guittot
2014-10-07 12:13 ` [PATCH v7 7/7] sched: add SD_PREFER_SIBLING for SMT level Vincent Guittot
2014-10-07 12:13 ` Vincent Guittot
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