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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/51798] [4.7 regression] libstdc++ atomicity performance regression due to __sync_fetch_and_add
Date: Wed, 25 Jan 2012 16:09:00 -0000	[thread overview]
Message-ID: <bug-51798-4-tXq3FOJf1g@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-51798-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51798

--- Comment #9 from Andrew Macleod <amacleod at redhat dot com> 2012-01-25 15:36:23 UTC ---
(In reply to comment #8)
> > At least at this point I'd feel much safer if libstdc++ used just acq_rel
> > semantics for the all atomic_fetch_and_add places, instead of somewhere acq and
> > somewhere rel semantics.
> 
> Can we at least apply the ACQ_REL patch using the new atomic intrinsics?
> 

Well, I thought that was implicit since I wasn't suggesting we change the
__sync semantics, just the required libstdc++ bits.  

All that has to be done is replace the two __sync_fetch_and_add(...) with
__atomic_fetch_add(.., __ATOMIC_ACQ_REL)  in atomicity.h isn't it?


  parent reply	other threads:[~2012-01-25 15:37 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-09 14:31 [Bug libstdc++/51798] New: " dje at gcc dot gnu.org
2012-01-09 14:36 ` [Bug libstdc++/51798] " dje at gcc dot gnu.org
2012-01-09 14:38 ` dje at gcc dot gnu.org
2012-01-09 15:43 ` rguenth at gcc dot gnu.org
2012-01-09 17:12 ` dje at gcc dot gnu.org
2012-01-24  7:45 ` amacleod at redhat dot com
2012-01-24 16:46 ` dje at gcc dot gnu.org
2012-01-24 16:51 ` amacleod at redhat dot com
2012-01-25 14:27 ` jakub at gcc dot gnu.org
2012-01-25 15:39 ` dje at gcc dot gnu.org
2012-01-25 16:09 ` amacleod at redhat dot com [this message]
2012-01-25 16:17 ` dje at gcc dot gnu.org
2012-01-26 13:52 ` jakub at gcc dot gnu.org
2012-01-26 14:38 ` amacleod at redhat dot com
2012-01-26 15:50 ` dje at gcc dot gnu.org
2012-01-26 15:53 ` redi at gcc dot gnu.org
2012-01-26 21:50 ` dje at gcc dot gnu.org
2012-01-26 22:08 ` redi at gcc dot gnu.org
2012-01-27 10:09 ` jakub at gcc dot gnu.org
2012-01-27 11:37 ` jakub at gcc dot gnu.org
2012-01-27 13:03 ` amacleod at redhat dot com
2012-01-27 14:55 ` dje at gcc dot gnu.org
2012-01-27 15:01 ` jakub at gcc dot gnu.org
2012-01-27 15:26 ` dje at gcc dot gnu.org
2012-01-27 20:15 ` bkoz at gcc dot gnu.org
2012-01-27 21:05 ` jakub at gcc dot gnu.org
2012-01-27 21:08 ` jakub at gcc dot gnu.org
2012-02-09  8:46 ` bkoz at gcc dot gnu.org
2012-02-09  9:16 ` redi at gcc dot gnu.org
2012-02-09 20:08 ` bkoz at gcc dot gnu.org
2012-02-09 23:22 ` bkoz at gcc dot gnu.org
2012-02-10 18:21 ` bkoz at gcc dot gnu.org
2012-02-13 21:31 ` rth at gcc dot gnu.org
2012-02-17 21:03 ` bkoz at gcc dot gnu.org

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