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From: Peter Zijlstra <peterz@infradead.org>
To: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>, Venki Pallipadi <venki@google.com>,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Mike Galbraith <efault@gmx.de>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Tim Chen <tim.c.chen@linux.jf.intel.com>,
	alex.shi@intel.com
Subject: Re: [patch 3/6] sched, nohz: sched group, domain aware nohz idle load balancing
Date: Thu, 24 Nov 2011 12:53:49 +0100	[thread overview]
Message-ID: <1322135629.2921.13.camel@twins> (raw)
In-Reply-To: <20111118230553.995756330@sbsiddha-desk.sc.intel.com>

On Fri, 2011-11-18 at 15:03 -0800, Suresh Siddha wrote:
> Make nohz idle load balancing more scalabale by using the nr_busy_cpus in
> the struct sched_group_power.
> 
> Idle load balance is kicked on one of the idle cpu's when there is atleast
> one idle cpu and
> 
>  - a busy rq having more than one task or
> 
>  - a busy scheduler group having multiple busy cpus that exceed the sched group
>    power or
> 
>  - for the SD_ASYM_PACKING domain, if the lower numbered cpu's in that
>    domain are idle compared to the busy ones.
> 
> This will help in kicking the idle load balancing request only when
> there is a real imbalance. And once it is mostly balanced, these kicks will
> be minimized.
> 
> These changes helped improve the workload that is context switch intensive
> between number of task pairs by 2x on a 8 socket NHM-EX based system.

OK, but the nohz idle balance will still iterate the whole machine
instead of smaller parts, right?



  parent reply	other threads:[~2011-11-24 11:54 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-18 23:03 [patch 0/6] sched, nohz: load balancing patches Suresh Siddha
2011-11-18 23:03 ` [patch 1/6] sched, nohz: introduce nohz_flags in the struct rq Suresh Siddha
2011-11-24 10:24   ` Peter Zijlstra
2011-11-28 23:59     ` Suresh Siddha
2011-11-29  9:47       ` Peter Zijlstra
2011-11-18 23:03 ` [patch 2/6] sched, nohz: track nr_busy_cpus in the sched_group_power Suresh Siddha
2011-11-18 23:03 ` [patch 3/6] sched, nohz: sched group, domain aware nohz idle load balancing Suresh Siddha
2011-11-24 11:47   ` Peter Zijlstra
2011-11-28 23:51     ` Suresh Siddha
2011-11-29  9:44       ` Peter Zijlstra
2011-12-01  1:03         ` Suresh Siddha
2011-12-01  1:17         ` Suresh Siddha
2011-12-01  8:36           ` Peter Zijlstra
2011-11-24 11:53   ` Peter Zijlstra [this message]
2011-11-28 23:58     ` Suresh Siddha
2011-11-29  9:45       ` Peter Zijlstra
2011-11-18 23:03 ` [patch 4/6] sched, nohz: cleanup the find_new_ilb() using sched groups nr_busy_cpus Suresh Siddha
2011-11-18 23:03 ` [patch 5/6] sched: disable sched feature TTWU_QUEUE by default Suresh Siddha
2011-11-19  4:30   ` Mike Galbraith
2011-11-19  4:41     ` Mike Galbraith
2011-11-18 23:03 ` [patch 6/6] sched: fix the sched group node allocation for SD_OVERLAP domain Suresh Siddha
2011-12-06  9:51   ` [tip:sched/core] sched: Fix the sched group node allocation for SD_OVERLAP domains tip-bot for Suresh Siddha

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