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From: "tudorb at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug libc/12518] memcpy acts randomly (and differently) with overlapping areas
Date: Tue, 20 Aug 2013 01:12:00 -0000	[thread overview]
Message-ID: <bug-12518-131-arpIXJ7YuP@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-12518-131@http.sourceware.org/bugzilla/>

http://sourceware.org/bugzilla/show_bug.cgi?id=12518

--- Comment #30 from Tudor Bosman <tudorb at gmail dot com> ---
(In reply to Ondrej Bilka from comment #29)
> Wait, do you have overlapping source and destination areas? If so then a
> backward copy is necessary.

Backward copy is often used for non-overlapping areas as it is faster on some
Intel processors; see https://bugzilla.redhat.com/show_bug.cgi?id=638477#c99
for an explanation. I was pointing out that it also has the (unintended)
behavior of pessimizing mmap()ed file accesses.

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  parent reply	other threads:[~2013-08-20  1:12 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-25  2:26 [Bug libc/12518] New: " torvalds@linux-foundation.org
2011-02-25  2:29 ` [Bug libc/12518] " torvalds@linux-foundation.org
2011-02-25  3:57 ` hjl.tools at gmail dot com
2011-02-25  4:15 ` torvalds@linux-foundation.org
2011-02-25  9:59 ` drepper.fsp at gmail dot com
2011-02-25 11:49 ` tolzmann at molgen dot mpg.de
2011-02-25 12:07 ` jakub at redhat dot com
2011-02-25 15:20 ` hjl.tools at gmail dot com
2011-02-26  1:56 ` drepper.fsp at gmail dot com
2011-03-02  4:03 ` alexander.hunt2005 at gmail dot com
2011-03-02 20:12 ` smconvey at gmail dot com
2011-03-03 23:28 ` felipe.contreras at gmail dot com
2011-03-04  3:02 ` jvillalo at redhat dot com
2011-03-04  9:28 ` thierry.vignaud at gmail dot com
2011-03-04 16:07 ` ml-bz-dale at riyescott dot com
2011-03-04 23:42 ` drepper.fsp at gmail dot com
2011-03-04 23:54 ` torvalds@linux-foundation.org
2011-03-05  0:28 ` felipe.contreras at gmail dot com
2011-03-05 13:28 ` oliver.henshaw at gmail dot com
2011-03-12 16:38 ` tmoody at ku dot edu
2011-03-24 21:04 ` bvasselle at gmail dot com
2011-03-25  4:37 ` hjl.tools at gmail dot com
2011-03-25  6:46 ` jakub at redhat dot com
2011-03-28 11:53 ` tmraz at redhat dot com
2011-03-28 11:54 ` felipe.contreras at gmail dot com
2011-03-29 14:43 ` felipe.contreras at gmail dot com
2011-03-29 22:28 ` bvasselle at gmail dot com
2011-03-30  5:14 ` felipe.contreras at gmail dot com
2011-03-30  7:21 ` felipe.contreras at gmail dot com
2011-03-30 10:20 ` y.pronenko at gmail dot com
2011-03-31  8:37 ` shaforostoff at gmail dot com
2011-04-01 23:42 ` drepper.fsp at gmail dot com
2011-04-02  2:57 ` hjl.tools at gmail dot com
2011-04-10 15:39 ` bvasselle at gmail dot com
2011-04-10 15:50 ` felipe.contreras at gmail dot com
2011-05-04 13:32 ` vincent+libc at vinc17 dot org
2011-05-04 15:02 ` felipe.contreras at gmail dot com
2011-06-07  3:07 ` kenyon at kenyonralph dot com
2013-08-12 17:20 ` tudorb at gmail dot com
2013-08-19 23:48   ` Ondřej Bílka
2013-08-19 23:48 ` neleai at seznam dot cz
2013-08-20  1:12 ` tudorb at gmail dot com [this message]
2014-02-16 19:41 ` jackie.rosen at hushmail dot com
2014-02-16 19:54 ` kenyon at kenyonralph dot com
2014-05-28 19:41 ` schwab at sourceware dot org
2014-06-27 13:49 ` fweimer at redhat dot com
2015-02-25 10:28 ` mwest@awek-microdata.de

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