From: Andi Kleen <andi@firstfloor.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@gentwo.org>,
Andrew Morton <akpm@linux-foundation.org>,
Dimitri Sivanich <sivanich@sgi.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] Reduce vm_stat cacheline contention in __vm_enough_memory
Date: Thu, 13 Oct 2011 08:59:49 -0700 [thread overview]
Message-ID: <m2hb3c287e.fsf@firstfloor.org> (raw)
In-Reply-To: <20111013150642.GC6169@csn.ul.ie> (Mel Gorman's message of "Thu, 13 Oct 2011 16:06:42 +0100")
Mel Gorman <mel@csn.ul.ie> writes:
>
> If vm_enough_memory is being heavily hit as well, it implies that this
> workload is mmap-intensive which is pretty inefficient in itself. I
Saw it with tmpfs originally. No need to be mmap intensive. Just
do lots of IOs on tmpfs.
> guess it would also apply to workloads that are malloc-intensive for
> large buffers but I'd expect the cache line bounces to only dominate if
> there was little or no computation on the resulting buffers.
I think you severly underestimate the costs of bouncing cache lines
on >2S.
> As a result, I wonder how realistic is this test workload and who useful
> fixing this problem is in general?
It's kind of bad if tmpfs doesn't scale.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <andi@firstfloor.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@gentwo.org>,
Andrew Morton <akpm@linux-foundation.org>,
Dimitri Sivanich <sivanich@sgi.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] Reduce vm_stat cacheline contention in __vm_enough_memory
Date: Thu, 13 Oct 2011 08:59:49 -0700 [thread overview]
Message-ID: <m2hb3c287e.fsf@firstfloor.org> (raw)
In-Reply-To: <20111013150642.GC6169@csn.ul.ie> (Mel Gorman's message of "Thu, 13 Oct 2011 16:06:42 +0100")
Mel Gorman <mel@csn.ul.ie> writes:
>
> If vm_enough_memory is being heavily hit as well, it implies that this
> workload is mmap-intensive which is pretty inefficient in itself. I
Saw it with tmpfs originally. No need to be mmap intensive. Just
do lots of IOs on tmpfs.
> guess it would also apply to workloads that are malloc-intensive for
> large buffers but I'd expect the cache line bounces to only dominate if
> there was little or no computation on the resulting buffers.
I think you severly underestimate the costs of bouncing cache lines
on >2S.
> As a result, I wonder how realistic is this test workload and who useful
> fixing this problem is in general?
It's kind of bad if tmpfs doesn't scale.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
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next prev parent reply other threads:[~2011-10-13 15:59 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-12 16:02 [PATCH] Reduce vm_stat cacheline contention in __vm_enough_memory Dimitri Sivanich
2011-10-12 19:01 ` Andrew Morton
2011-10-12 19:01 ` Andrew Morton
2011-10-12 19:57 ` Christoph Lameter
2011-10-12 19:57 ` Christoph Lameter
2011-10-13 15:06 ` Mel Gorman
2011-10-13 15:06 ` Mel Gorman
2011-10-13 15:59 ` Andi Kleen [this message]
2011-10-13 15:59 ` Andi Kleen
2011-10-13 15:23 ` Dimitri Sivanich
2011-10-13 15:23 ` Dimitri Sivanich
2011-10-13 15:54 ` Christoph Lameter
2011-10-13 15:54 ` Christoph Lameter
2011-10-13 20:50 ` Andrew Morton
2011-10-13 20:50 ` Andrew Morton
2011-10-13 21:02 ` Christoph Lameter
2011-10-13 21:02 ` Christoph Lameter
2011-10-13 21:24 ` Andrew Morton
2011-10-13 21:24 ` Andrew Morton
2011-10-14 12:25 ` Dimitri Sivanich
2011-10-14 12:25 ` Dimitri Sivanich
2011-10-14 13:50 ` Dimitri Sivanich
2011-10-14 13:50 ` Dimitri Sivanich
2011-10-14 13:57 ` Christoph Lameter
2011-10-14 13:57 ` Christoph Lameter
2011-10-14 14:19 ` Dimitri Sivanich
2011-10-14 14:19 ` Dimitri Sivanich
2011-10-14 14:34 ` Christoph Lameter
2011-10-14 14:34 ` Christoph Lameter
2011-10-14 15:18 ` Christoph Lameter
2011-10-14 15:18 ` Christoph Lameter
2011-10-14 16:16 ` Dimitri Sivanich
2011-10-14 16:16 ` Dimitri Sivanich
2011-10-18 13:48 ` Dimitri Sivanich
2011-10-18 13:48 ` Dimitri Sivanich
2011-10-18 14:36 ` Christoph Lameter
2011-10-18 14:36 ` Christoph Lameter
2011-10-18 15:48 ` Andi Kleen
2011-10-18 15:48 ` Andi Kleen
2011-10-19 1:16 ` David Rientjes
2011-10-19 1:16 ` David Rientjes
2011-10-19 14:54 ` Dimitri Sivanich
2011-10-19 14:54 ` Dimitri Sivanich
2011-10-19 15:31 ` Christoph Lameter
2011-10-19 15:31 ` Christoph Lameter
2011-10-24 14:59 ` Dimitri Sivanich
2011-10-24 14:59 ` Dimitri Sivanich
[not found] ` <CADE8fzrdMOBF1RyyEpMVi8aKcgOVKRQSKi0=c1Qvh3p6hHcXRA@mail.gmail.com>
2011-10-13 0:07 ` Tim Chen
2011-10-13 0:07 ` Tim Chen
2011-10-13 14:15 ` Christoph Lameter
2011-10-13 14:15 ` Christoph Lameter
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