linux-kernel - Re: [RFC PATCH] sched/numa: do load balance between remote nodes

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Date:	Wed, 06 Jun 2012 14:53:08 +0400
From:	Sergei Shtylyov <sshtylyov@...sta.com>
To:	Alex Shi <alex.shi@...el.com>
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Subject: Re: [RFC PATCH] sched/numa: do load balance between remote nodes

Hello.

On 06-06-2012 10:52, Alex Shi wrote:

> commit cb83b629b

    Please also specify that commit's summary in parens.

> remove the NODE sched domain and check if the node
> distance in SLIT table is farther than REMOTE_DISTANCE, if so, it will
> lose the load balance chance at exec/fork/wake_affine points.

> But actually, even the node distance is farther than REMOTE_DISTANCE,
> Modern CPUs also has QPI like connections, that make memory access is

    "Is" not needed here.

> not too slow between nodes.  So above losing on NUMA machine make a
> huge performance regression on benchmark: hackbench, tbench, netperf
> and oltp etc.

> This patch will recover the scheduler behavior to old mode on all my
> Intel platforms: NHM EP/EX, WSM EP, SNB EP/EP4S, and so remove the
> perfromance regressions. (all of them just has 2 kinds distance, 10 21)

> Signed-off-by: Alex Shi<alex.shi@...el.com>

WBR, Sergei
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