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From: "hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/43052] Inline memcmp is *much* slower than glibc's
Date: Mon, 04 Jul 2011 10:50:00 -0000	[thread overview]
Message-ID: <bug-43052-4-viv19WRM5z@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-43052-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43052

--- Comment #12 from Jan Hubicka <hubicka at gcc dot gnu.org> 2011-07-04 10:49:18 UTC ---
Created attachment 24670
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24670
memcpy/memset testing script

HJ,
can you please run the attached script with new glibc as 
sh test_stringop 64 640000000 gcc -march=native | tee out

In my quick testing on glibc2.11 and core i5 & AMD machine, inline
memcpy/memset is still win on I5 for all blocks sizes (our optimization table
is however wrong since it is inherited from generic one). For blocks of 512b
and above however the inline code is about as fast as glibc code and obviously
longer.

On AMD machine libcall is win for blocks of 1k to 8k. For large blocks inline
seems to be win again, for whatever reason. Probably prefetch logic is wrong on
the older glibc.

If glibc stringops has been finally made sane, we ought to revisit the tables
we generate inline versions from.


  parent reply	other threads:[~2011-07-04 10:50 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-43052-4@http.gcc.gnu.org/bugzilla/>
2010-10-01 11:08 ` [Bug c/43052] " m.j.thayer at googlemail dot com
2010-11-10 21:17 ` [Bug target/43052] " hubicka at gcc dot gnu.org
2010-11-10 21:36 ` hubicka at gcc dot gnu.org
2010-11-11  2:24 ` hjl.tools at gmail dot com
2010-11-11 10:40 ` rguenth at gcc dot gnu.org
2010-11-11 11:47 ` jakub at gcc dot gnu.org
2011-06-13 18:10 ` justin.lebar+bug at gmail dot com
2011-06-13 18:14 ` hjl.tools at gmail dot com
2011-06-13 18:19 ` justin.lebar+bug at gmail dot com
2011-07-04 10:13 ` hubicka at gcc dot gnu.org
2011-07-04 10:50 ` hubicka at gcc dot gnu.org [this message]
2011-07-04 14:42 ` justin.lebar+bug at gmail dot com
2011-07-04 15:03 ` justin.lebar+bug at gmail dot com
2011-07-05 11:10 ` hubicka at ucw dot cz
2011-08-24 10:58 ` [Bug target/43052] [4.7 Regression] Inline memcmp is *much* slower than glibc's, no longer expanded inline rguenth at gcc dot gnu.org
2011-08-24 14:36 ` hubicka at gcc dot gnu.org
2011-08-24 14:45 ` rguenth at gcc dot gnu.org
2011-10-10 11:33 ` rguenth at gcc dot gnu.org
2011-12-21 17:19 ` fabio.ped at libero dot it
2012-03-22  9:18 ` [Bug target/43052] [4.7/4.8 " rguenth at gcc dot gnu.org
2012-06-14  8:38 ` rguenth at gcc dot gnu.org
2012-09-20 10:28 ` jakub at gcc dot gnu.org
2013-03-13 20:14 ` steven at gcc dot gnu.org
2013-04-11  8:00 ` [Bug target/43052] [4.7/4.8/4.9 " rguenth at gcc dot gnu.org
2014-06-12 13:49 ` [Bug target/43052] [4.7/4.8/4.9/4.10 " rguenth at gcc dot gnu.org
2014-12-19 13:34 ` [Bug target/43052] [4.8/4.9/5 " jakub at gcc dot gnu.org
2015-03-20 21:27 ` hubicka at gcc dot gnu.org
2015-06-23  8:28 ` [Bug target/43052] [4.8/4.9/5/6 " rguenth at gcc dot gnu.org
2015-06-26 20:04 ` [Bug target/43052] [4.9/5/6 " jakub at gcc dot gnu.org
2015-06-26 20:32 ` jakub at gcc dot gnu.org

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