From: Morten Rasmussen <morten.rasmussen@arm.com>
To: Alex Shi <alex.shi@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Jason Low <jason.low2@hp.com>, Ingo Molnar <mingo@redhat.com>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
Mike Galbraith <efault@gmx.de>,
"wangyun@linux.vnet.ibm.com" <wangyun@linux.vnet.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] sched: add statistic for rq->max_idle_balance_cost
Date: Thu, 23 Jan 2014 12:32:52 +0000 [thread overview]
Message-ID: <20140123123252.GC19029@e103034-lin> (raw)
In-Reply-To: <52E0F3BF.5020904@linaro.org>
On Thu, Jan 23, 2014 at 10:49:35AM +0000, Alex Shi wrote:
> On 01/23/2014 05:54 PM, Peter Zijlstra wrote:
> > On Thu, Jan 23, 2014 at 02:49:25PM +0800, Alex Shi wrote:
> >> On 01/23/2014 02:10 AM, Jason Low wrote:
> >>>>>>> P64(avg_idle);
> >>>>>>> + P64(max_idle_balance_cost);
> >>>>>>> #endif
> >>>>>>> P(ttwu_count);
> >>>>>
> >>>>> Not also the per-sd value in sd_alloc_ctl_domain_table() ?
> >>> Yeah, tracking the sd->max_newidle_lb_cost can also be useful.
> >>>
> >>>
> >>
> >> Thanks for suggestion!
> >>
> >> I thought the sd->max_newidle_lb_cost keep changing. But yes, it's
> >> still meaningful.
> >> BTW, in the pandaboard ES, sd balance cost is about 1~2ms.
> >
> > That's an insane amount of time for only 2 cpus.
>
> maybe, :(
>
> but it is the data.
> $ cat /proc/sys/kernel/sched_domain/cpu0/domain0/max_newidle_lb_cost
> 1873393
What sort of workload are you running? It seems rather extreme.
I did a quick test on TC2 and got max_newidle_lb_cost in the range
~7000-80000 when having a constantly running task on each cpu for a few
seconds.
I also traced curr_cost just to get an idea of the cost of idle_balance.
I get an average cost across all five cpus of around 7000.
Morten
next prev parent reply other threads:[~2014-01-23 12:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-21 5:33 [RFC PATCH 1/2] sched/update_avg: avoid negative time Alex Shi
2014-01-21 5:33 ` [PATCH 2/2] sched: add statistic for rq->max_idle_balance_cost Alex Shi
2014-01-21 7:43 ` Jason Low
2014-01-21 8:44 ` Alex Shi
2014-01-22 8:24 ` Alex Shi
2014-01-22 16:09 ` Peter Zijlstra
2014-01-22 18:10 ` Jason Low
2014-01-23 6:49 ` Alex Shi
2014-01-23 9:54 ` Peter Zijlstra
2014-01-23 10:49 ` Alex Shi
2014-01-23 12:32 ` Morten Rasmussen [this message]
2014-01-23 14:43 ` Alex Shi
2014-02-11 12:17 ` [tip:sched/core] sched: Add statistic for newidle load balance cost tip-bot for Alex Shi
2014-01-21 5:59 ` [RFC PATCH 1/2] sched/update_avg: avoid negative time Alex Shi
2014-01-21 6:49 ` Michael wang
2014-01-21 8:46 ` Alex Shi
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