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From: "Joseph S. Myers" <joseph@codesourcery.com>
To: Dinar Temirbulatov <dinar@kugelworks.com>
Cc: <libc-ports@sourceware.org>, <adeb@nvidia.com>
Subject: Re: [Patch] ARM define atomic_exchange_acq/atomic_exchange_rel to __atomic_exchange_n
Date: Sun, 18 Aug 2013 20:29:00 -0000	[thread overview]
Message-ID: <Pine.LNX.4.64.1308182022000.10353@digraph.polyomino.org.uk> (raw)
In-Reply-To: <CANoaTN2hKTZ7GZCMsYqai25PHO7GLb56huLosR7+dgjAEK2FGQ@mail.gmail.com>

On Tue, 13 Aug 2013, Dinar Temirbulatov wrote:

> Hello,
> Following patch redefines atomic_exchange_acq/atomic_exchange_rel to
> __atomic_exchange_n for ARM, that allows for example to reduce number
> of instruction sequence for lll_unlock
> from:
> ldex, cmp, bne, stex, cmp, bne
> to
> ldex, stex, cmp, bne
> , more on the issue here:
> http://sourceware.org/bugzilla/show_bug.cgi?id=15640
> 
> This patch was tested on ARM a9 with glibc testsuite with no new
> regressions. OK to commit?

What does this do when building for an ARM architecture version where the 
kernel helpers need to be used for atomicity?

I think what's desired in such a case is for the operations to continue to 
be expanded with inline calls to the kernel helpers.  Generating 
out-of-line calls to libgcc helpers would be less desirable (and 
out-of-line calls to anything not in libgcc.a would break the build).

-- 
Joseph S. Myers
joseph@codesourcery.com

  parent reply	other threads:[~2013-08-18 20:29 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-13 17:11 Dinar Temirbulatov
2013-08-15 21:46 ` Abhishek Deb
2013-08-16 22:57   ` Dinar Temirbulatov
2013-08-17  2:42     ` Abhishek Deb
2013-08-19 19:21       ` Dinar Temirbulatov
2013-08-18 20:29 ` Joseph S. Myers [this message]
2013-09-01 20:42 Dinar Temirbulatov
2013-09-01 20:43 Dinar Temirbulatov
2013-09-02 15:08 ` Joseph S. Myers
2013-09-03 17:31   ` Abhishek Deb
2013-09-05 12:56   ` Dinar Temirbulatov
2013-09-05 15:48     ` Joseph S. Myers
2013-09-05 17:09       ` Abhishek Deb
2013-09-11 19:25         ` Dinar Temirbulatov
2013-09-11 19:27         ` Dinar Temirbulatov
2013-09-11 20:40           ` Abhishek Deb
2013-09-13 17:14           ` Joseph S. Myers
2013-09-14  3:29             ` Dinar Temirbulatov
2013-09-18 17:16               ` Joseph S. Myers
2013-09-19  6:53                 ` Maxim Kuvyrkov
2013-09-19 16:29                   ` Joseph S. Myers

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