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From: Thomas Gleixner <>
To: Andi Kleen <>
Cc: Andrew Morton <>,
	LKML <>,
	Andi Kleen <>
Subject: Re: [PATCH] Allocate idle task for a CPU always on its local node
Date: Wed, 18 May 2016 10:28:43 +0200 (CEST)
Message-ID: <alpine.DEB.2.11.1605181028220.3851@nanos> (raw)
In-Reply-To: <>

On Tue, 17 May 2016, Andi Kleen wrote:
> From: Andi Kleen <>
> Linux pre-allocates the task structs of the idle tasks for all possible CPUs.
> This currently means they all end up on node 0. This also implies
> that the cache line of MWAIT, which is around the flags field in the task
> struct, are all located in node 0.
> We see a noticeable performance improvement on Knights Landing CPUs when
> the cache lines used for MWAIT are located in the local nodes of the CPUs
> using them. I would expect this to give a (likely slight) improvement
> on other systems too.
> The patch implements placing the idle task in the node of
> its CPUs, by passing the right target node to copy_process()
> Signed-off-by: Andi Kleen <>

Acked-by: Thomas Gleixner <>

      parent reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-17 13:44 Andi Kleen
2016-05-17 21:13 ` Andrew Morton
2016-05-17 21:50   ` Andi Kleen
2016-05-18  8:28 ` Thomas Gleixner [this message]

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