From: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
To: Davidlohr Bueso <davidlohr@hp.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: kosaki.motohiro@gmail.com, Hugh Dickins <hughd@google.com>,
Michel Lespinasse <walken@google.com>,
Ingo Molnar <mingo@kernel.org>, Mel Gorman <mgorman@suse.de>,
Rik van Riel <riel@redhat.com>, Guan Xuetao <gxt@mprc.pku.edu.cn>,
aswin@hp.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: cache largest vma
Date: Fri, 01 Nov 2013 16:38:35 -0400 [thread overview]
Message-ID: <5274114B.7010302@gmail.com> (raw)
In-Reply-To: <1383337039.2653.18.camel@buesod1.americas.hpqcorp.net>
(11/1/13 4:17 PM), Davidlohr Bueso wrote:
> While caching the last used vma already does a nice job avoiding
> having to iterate the rbtree in find_vma, we can improve. After
> studying the hit rate on a load of workloads and environments,
> it was seen that it was around 45-50% - constant for a standard
> desktop system (gnome3 + evolution + firefox + a few xterms),
> and multiple java related workloads (including Hadoop/terasort),
> and aim7, which indicates it's better than the 35% value documented
> in the code.
>
> By also caching the largest vma, that is, the one that contains
> most addresses, there is a steady 10-15% hit rate gain, putting
> it above the 60% region. This improvement comes at a very low
> overhead for a miss. Furthermore, systems with !CONFIG_MMU keep
> the current logic.
I'm slightly surprised this cache makes 15% hit. Which application
get a benefit? You listed a lot of applications, but I'm not sure
which is highly depending on largest vma.
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next prev parent reply other threads:[~2013-11-01 20:38 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-01 20:17 [PATCH] mm: cache largest vma Davidlohr Bueso
2013-11-01 20:38 ` KOSAKI Motohiro [this message]
2013-11-01 21:11 ` Davidlohr Bueso
2013-11-03 9:46 ` Ingo Molnar
2013-11-03 23:57 ` KOSAKI Motohiro
2013-11-04 4:22 ` Davidlohr Bueso
2013-11-01 21:23 ` Rik van Riel
2013-11-03 10:12 ` Ingo Molnar
2013-11-04 4:20 ` Davidlohr Bueso
2013-11-04 4:48 ` converting unicore32 to gate_vma as done for arm (was Re: [PATCH] mm: cache largest vma) Al Viro
2013-11-05 2:49 ` 管雪涛
2013-11-11 7:25 ` converting unicore32 to gate_vma as done for arm (was " Al Viro
2013-11-04 7:00 ` [PATCH] mm: cache largest vma Ingo Molnar
2013-11-04 7:05 ` Ingo Molnar
2013-11-04 14:20 ` Frederic Weisbecker
2013-11-04 17:52 ` Ingo Molnar
2013-11-04 18:10 ` Frederic Weisbecker
2013-11-05 8:24 ` Ingo Molnar
2013-11-05 14:27 ` Jiri Olsa
2013-11-06 6:01 ` Ingo Molnar
2013-11-06 14:03 ` Konstantin Khlebnikov
2013-11-03 18:51 ` Linus Torvalds
2013-11-04 4:04 ` Davidlohr Bueso
2013-11-04 7:36 ` Ingo Molnar
2013-11-04 14:56 ` Michel Lespinasse
2013-11-11 4:12 ` Davidlohr Bueso
2013-11-11 7:43 ` Michel Lespinasse
2013-11-11 12:04 ` Ingo Molnar
2013-11-11 20:47 ` Davidlohr Bueso
2013-11-13 17:08 ` Davidlohr Bueso
2013-11-13 17:59 ` Ingo Molnar
2013-11-13 18:16 ` Peter Zijlstra
2013-11-11 12:01 ` Ingo Molnar
2013-11-11 18:24 ` Davidlohr Bueso
2013-11-11 20:47 ` Ingo Molnar
2013-11-11 20:59 ` Davidlohr Bueso
2013-11-11 21:09 ` Ingo Molnar
2013-11-04 7:03 ` Christoph Hellwig
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