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From: Christoph Lameter <cl@linux.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Paul Turner <pjt@google.com>,
	Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
	Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 0/8] Announcement: Enhanced NUMA scheduling with adaptive affinity
Date: Fri, 16 Nov 2012 20:57:31 +0000	[thread overview]
Message-ID: <0000013b0b031a8f-e57805ad-a81f-4aa7-9906-ceb99f41210b-000000@email.amazonses.com> (raw)
In-Reply-To: <20121116155943.GB4271@gmail.com>

On Fri, 16 Nov 2012, Ingo Molnar wrote:

> > The interleaving of memory areas that have an equal amount of
> > shared accesses from multiple nodes is essential to limit the
> > traffic on the interconnect and get top performance.
>
> That is true only if the load is symmetric.

Which is usually true of an HPC workload.

> > I guess through that in a non HPC environment where you are
> > not interested in one specific load running at top speed
> > varying contention on the interconnect and memory busses are
> > acceptable. But this means that HPC loads cannot be auto
> > tuned.
>
> I'm not against improving these workloads (at all) - I just
> pointed out that interleaving isn't necessarily the best
> placement strategy for 'large' workloads.

Depends on what you mean by "large" workloads. If it is a typically large
HPC workload with data structures distributed over nodes then the
placement of those data structure spread over all nodes is the best
placement startegy.

      reply	other threads:[~2012-11-16 20:57 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-12 16:04 [PATCH 0/8] Announcement: Enhanced NUMA scheduling with adaptive affinity Peter Zijlstra
2012-11-12 16:04 ` [PATCH 1/8] sched, numa, mm: Introduce sched_feat_numa() Peter Zijlstra
2012-11-12 16:04 ` [PATCH 2/8] sched, numa, mm: Implement THP migration Peter Zijlstra
2012-11-12 16:04 ` [PATCH 3/8] sched, numa, mm: Add credits for NUMA placement Peter Zijlstra
2012-11-12 16:04 ` [PATCH 4/8] sched, numa, mm: Add last_cpu to page flags Peter Zijlstra
2012-11-13 11:55   ` Ingo Molnar
2012-11-13 16:09   ` Rik van Riel
2012-11-12 16:04 ` [PATCH 5/8] sched, numa, mm: Add adaptive NUMA affinity support Peter Zijlstra
2012-11-13  0:02   ` Christoph Lameter
2012-11-13  8:19     ` Ingo Molnar
2012-11-13 22:57   ` Rik van Riel
2012-11-16 18:06   ` Rik van Riel
2012-11-16 18:14     ` Ingo Molnar
2012-11-16 18:23       ` Rik van Riel
2012-11-29 19:34   ` Andi Kleen
2012-11-12 16:04 ` [PATCH 6/8] sched, numa, mm: Implement constant, per task Working Set Sampling (WSS) rate Peter Zijlstra
2012-11-12 16:04 ` [PATCH 7/8] sched, numa, mm: Count WS scanning against present PTEs, not virtual memory ranges Peter Zijlstra
2012-11-12 16:04 ` [PATCH 8/8] sched, numa, mm: Implement slow start for working set sampling Peter Zijlstra
2012-11-12 18:48 ` Benchmark results: "Enhanced NUMA scheduling with adaptive affinity" Ingo Molnar
2012-11-15 10:08   ` Mel Gorman
2012-11-15 18:52     ` Rik van Riel
2012-11-15 21:27       ` Mel Gorman
2012-11-15 20:32     ` Linus Torvalds
2012-11-15 22:04       ` Rik van Riel
2012-11-16 14:14         ` Mel Gorman
2012-11-16 19:50           ` Andrea Arcangeli
2012-11-16 20:05             ` Mel Gorman
2012-11-16 16:16       ` Ingo Molnar
2012-11-16 15:56     ` Ingo Molnar
2012-11-16 16:25       ` Mel Gorman
2012-11-16 17:49         ` Ingo Molnar
2012-11-16 19:04           ` Mel Gorman
2012-11-12 23:43 ` [PATCH 0/8] Announcement: Enhanced NUMA scheduling with adaptive affinity Christoph Lameter
2012-11-13  7:24   ` Ingo Molnar
2012-11-15 14:26     ` Christoph Lameter
2012-11-16 15:59       ` Ingo Molnar
2012-11-16 20:57         ` Christoph Lameter [this message]

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