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From: Alex Shi <alex.shi@linaro.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
	"fweisbec@gmail.com" <fweisbec@gmail.com>,
	"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
	"tony.luck@intel.com" <tony.luck@intel.com>,
	"fenghua.yu@intel.com" <fenghua.yu@intel.com>,
	"james.hogan@imgtec.com" <james.hogan@imgtec.com>,
	"jason.low2@hp.com" <jason.low2@hp.com>,
	"viresh.kumar@linaro.org" <viresh.kumar@linaro.org>,
	"hanjun.guo@linaro.org" <hanjun.guo@linaro.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"arjan@linux.intel.com" <arjan@linux.intel.com>,
	"pjt@google.com" <pjt@google.com>,
	"fengguang.wu@intel.com" <fengguang.wu@intel.com>,
	"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
	"wangyun@linux.vnet.ibm.com" <wangyun@linux.vnet.ibm.com>
Subject: Re: [PATCH v2 0/11] remove cpu_load in rq
Date: Wed, 19 Feb 2014 18:23:34 +0800	[thread overview]
Message-ID: <53048626.2000803@linaro.org> (raw)
In-Reply-To: <CAKfTPtDtv=hFtprNpAfRVMEAvWZn-55u8fcHTdJT6xT92Qdt-g@mail.gmail.com>


>> Removing cpu_load completely certainly makes things simpler, my worry is
>> just how much was lost by doing it. I agree that cpu_load needs a
>> cleanup, but I can't convince myself that just removing it completely
>> and not having any longer term view of cpu load anymore is without any
>> negative side-effects.
> 
> Hi Alex,
> 
> Have you followed this thread about load_idx and the interest of using
> them to use different average period ?
> https://lkml.org/lkml/2014/1/6/499

Yes, I hoped to use blocked load before. But I still can not figure out
the correct usage of it.
Or maybe we need more quick decay for blocked load?
Or, maybe clean cpu_load is helpful to make room to reconsider this.
> 
> Vincent
> 
>>
>> {source, target}_load() are now instantaneous views of the cpu load,
>> which means that they may change very frequently. That could potentially
>> lead to more task migrations at all levels in the domain hierarchy as we
>> no longer have the more conservative cpu_load[] indexes that were used
>> at NUMA level.
>>
>> Maybe some of the NUMA experts have an opinion about this?
>>
>> In the discussions around V1 I think blocked load came up again as a
>> potential replacement for the current cpu_load array. There are some
>> issues that need to be solved around blocked_load first though.
>>
>> Morten


-- 
Thanks
    Alex

      reply	other threads:[~2014-02-19 10:24 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-17  1:55 [PATCH v2 0/11] remove cpu_load in rq Alex Shi
2014-02-17  1:55 ` [PATCH v2 01/11] sched: shortcut to remove load_idx Alex Shi
2014-02-17  1:55 ` [PATCH v2 02/11] sched: remove rq->cpu_load[load_idx] array Alex Shi
2014-02-17  1:55 ` [PATCH v2 03/11] sched: clean up cpu_load update Alex Shi
2014-02-17  1:55 ` [PATCH v2 04/11] sched: unify imbalance bias for target group Alex Shi
2014-02-17  1:55 ` [PATCH v2 05/11] sched: rewrite update_cpu_load_nohz Alex Shi
2014-02-17  1:55 ` [PATCH v2 06/11] sched: clean up source_load/target_load Alex Shi
2014-02-17  1:55 ` [PATCH v2 07/11] sched: clean up weighted_cpuload Alex Shi
2014-02-17  1:55 ` [PATCH v2 08/11] sched: remove weighted_load() Alex Shi
2014-02-17  1:55 ` [PATCH v2 09/11] sched: remove rq->cpu_load and rq->nr_load_updates Alex Shi
2014-02-17  1:55 ` [PATCH v2 10/11] sched: rename update_*_cpu_load Alex Shi
2014-02-17  1:55 ` [PATCH v2 11/11] sched: clean up task_hot function Alex Shi
2014-02-18  2:37 ` [PATCH v2 0/11] remove cpu_load in rq Alex Shi
2014-02-18  4:52 ` Michael wang
2014-02-18  6:03   ` Alex Shi
2014-02-18  6:17     ` Michael wang
     [not found] ` <20140218120522.GG19029@e103034-lin>
2014-02-18 12:28   ` Vincent Guittot
2014-02-19 10:23     ` Alex Shi [this message]

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