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From: Steven Rostedt <rostedt@goodmis.org>
To: Xunlei Pang <pang.xunlei@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Juri Lelli <juri.lelli@gmail.com>
Subject: Re: [PATCH 5/5] sched/rt: Optimize find_lowest_rq() to select a cache hot cpu
Date: Thu, 29 Jan 2015 12:17:39 -0500	[thread overview]
Message-ID: <20150129121739.5a9b4b99@gandalf.local.home> (raw)
In-Reply-To: <CADcy93X5zcw04UyW19hFSVczeT6HoGXq2poOcODmEiUw_Mab0w@mail.gmail.com>

On Fri, 30 Jan 2015 00:42:47 +0800
Xunlei Pang <pang.xunlei@linaro.org> wrote:

 
> I think the responsiveness is the most important feature for RT tasks,
> so I think:
> response latency > cache > SMT in significance.

Unfortunately, sometimes cache affects response latency.

> 
> I was wondering if we can take the cpuidle state into account like
> current find_idlest_cpu() for CFS?
> cpupri_find() can be easily modified to indicate the CPUPRI_IDLE case,
> then we can select
> an optimal idle cpu to improve RT tasks' responsiveness. For other
> cases(mostly non-idle cpu),

Even if that idle cpu happens to be on another NUMA node?

-- Steve

> I think we can rely on the existent sched_domain iteraction to select
> a cache-hot cpu without
> caring too much about SMT.



  reply	other threads:[~2015-01-29 17:17 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-19  4:49 [PATCH 1/5] sched/deadline: Modify cpudl::free_cpus to reflect rd->online Xunlei Pang
2015-01-19  4:49 ` [PATCH 2/5] sched/deadline: Remove cpu_active_mask from cpudl_find() Xunlei Pang
2015-01-27 15:04   ` Peter Zijlstra
2015-02-04 14:36   ` [tip:sched/core] " tip-bot for Xunlei Pang
2015-01-19  4:49 ` [PATCH 3/5] sched/deadline: Fix wrong cpudl_find() in check_preempt_equal_dl() Xunlei Pang
2015-01-27 12:48   ` Peter Zijlstra
2015-01-27 14:15     ` Peter Zijlstra
2015-01-27 16:47   ` Peter Zijlstra
2015-01-28 15:18     ` Xunlei Pang
2015-01-19  4:49 ` [PATCH 4/5] sched/rt: Consider deadline tasks in cpupri_find() Xunlei Pang
2015-01-27 12:58   ` Peter Zijlstra
2015-01-27 14:18     ` Peter Zijlstra
2015-01-27 23:04     ` Steven Rostedt
2015-01-28 15:21       ` Xunlei Pang
2015-01-19  4:49 ` [PATCH 5/5] sched/rt: Optimize find_lowest_rq() to select a cache hot cpu Xunlei Pang
2015-01-27 14:21   ` Peter Zijlstra
2015-01-27 14:56     ` Steven Rostedt
2015-01-27 16:28       ` Peter Zijlstra
2015-01-29 16:42       ` Xunlei Pang
2015-01-29 17:17         ` Steven Rostedt [this message]
2015-01-29 19:23         ` Peter Zijlstra
2015-02-04 13:07           ` Xunlei Pang
2015-01-23 18:09 ` [PATCH 1/5] sched/deadline: Modify cpudl::free_cpus to reflect rd->online Xunlei Pang
2015-02-01 17:53 ` [tip:sched/core] sched/deadline: Modify cpudl:: free_cpus " tip-bot for Xunlei Pang

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