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Re: gcc 4.1 implements compiler builtins for atomic ops
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Benjamin Herrenschmidt <benh at kernel dot crashing dot org>, Anuj Goyal <anuj dot goyal at gmail dot com>, hollis at penguinppc dot org, libc-alpha at sources dot redhat dot com, roland at redhat dot com
- Date: Sun, 26 Jun 2005 21:23:40 +0200
- Subject: Re: gcc 4.1 implements compiler builtins for atomic ops
- References: <2f225d01050625091875932e04@mail.gmail.com> <7a02832e219e2e6ceca78f06264d7a94@penguinppc.org> <1119742835.5133.12.camel@gaston> <2f225d0105062519451d9e9c85@mail.gmail.com> <1119767813.5133.16.camel@gaston> <20050626155342.GA30210@nevyn.them.org>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Sun, Jun 26, 2005 at 11:53:43AM -0400, Daniel Jacobowitz wrote:
> On Sun, Jun 26, 2005 at 04:36:53PM +1000, Benjamin Herrenschmidt wrote:
> > Well, we have _at_least_ 40x which needs a sync in there, and you really
> > don't want a sync on other processors for performance reasons. As soon
>
> GCC already supports atomic operations on many platforms. GCC will
> support the 405CR erratum, next week or so. David's been working on
> it.
>
> Let's face it - enough people dislike the overhead of a function call
> for this that if glibc implemented them, they'd be inline functions,
> and you'd have all the same problems.
Well, glibc implements them already, though not in an installed header.
See <atomic.h> and arch specific <bits/atomic.h> it uses.
Jakub