From: Paulo Marques <pmarques@grupopie.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Rik van Riel <riel@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC] mmaped copy too slow?
Date: Tue, 15 Jan 2008 12:46:29 +0000 [thread overview]
Message-ID: <478CAB25.30300@grupopie.com> (raw)
In-Reply-To: <20080115100450.1180.KOSAKI.MOTOHIRO@jp.fujitsu.com>
KOSAKI Motohiro wrote:
> Hi
>
> at one point, I found the large file copy speed was different depending on
> the copy method.
>
> I compared below method
> - read(2) and write(2).
> - mmap(2) x2 and memcpy.
> - mmap(2) and write(2).
>
> in addition, effect of fadvice(2) and madvice(2) is checked.
>
> to a strange thing,
> - most faster method is read + write + fadvice.
> - worst method is mmap + memcpy.
One thing you could also try is to pass MAP_POPULATE to mmap so that the
page tables are filled in at the time of the mmap, avoiding a lot of
page faults later.
Just my 2 cents,
--
Paulo Marques - www.grupopie.com
"All I ask is a chance to prove that money can't make me happy."
--
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next prev parent reply other threads:[~2008-01-15 12:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-15 1:45 KOSAKI Motohiro
2008-01-15 2:15 ` Rik van Riel
2008-01-15 3:20 ` KOSAKI Motohiro
2008-01-15 8:57 ` Peter Zijlstra
2008-01-15 9:03 ` KOSAKI Motohiro
2008-01-15 9:08 ` Peter Zijlstra
2008-01-15 12:46 ` Paulo Marques [this message]
2008-01-16 2:05 ` KOSAKI Motohiro
2008-01-17 3:23 ` KOSAKI Motohiro
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