From: Chris Snook <csnook@redhat.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Andi Kleen <ak@suse.de>,
sebastian@breakpoint.cc, linux-kernel@vger.kernel.org
Subject: Re: [patch 1/2] i386: use asm() like the other atomic operations already do.
Date: Wed, 15 Aug 2007 13:02:23 -0400 [thread overview]
Message-ID: <46C3319F.4050809@redhat.com> (raw)
In-Reply-To: <E1ILEQ8-0005H5-00@gondolin.me.apana.org.au>
Herbert Xu wrote:
> Andi Kleen <ak@suse.de> wrote:
>>> My config with march=pentium-m and gcc (GCC) 4.1.2 (Gentoo 4.1.2):
>>> text data bss dec hex filename
>>> 3434150 249176 176128 3859454 3ae3fe atomic_normal/vmlinux
>>> 3435308 249176 176128 3860612 3ae884 atomic_inlineasm/vmlinux
>> What is the difference between atomic_normal and atomic_inlineasm?
>
> The inline asm stops certain optimisations from occuring.
>
> I'm still unconvinced why we need this because nobody has
> brought up any examples of kernel code that legitimately
> need this.
There's plenty of kernel code that *wants* this though. If we can
reduce the need for register-clobbering barriers, shrink our binaries,
shrink our code, improve performance, and avoid heisenbugs, I think it's
a win, whether or not we *need* it.
-- Chris
next prev parent reply other threads:[~2007-08-15 17:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-14 22:38 [patch 0/2] use asm() for atomic_{read|set} Sebastian Siewior
2007-08-14 22:38 ` [patch 1/2] i386: use asm() like the other atomic operations already do Sebastian Siewior
2007-08-15 0:20 ` Andi Kleen
2007-08-15 7:04 ` Sebastian Siewior
2007-08-15 8:40 ` Herbert Xu
2007-08-15 13:02 ` Satyam Sharma
2007-08-15 13:45 ` Sebastian Siewior
2007-08-15 17:02 ` Chris Snook [this message]
2007-08-15 23:44 ` Herbert Xu
2007-08-16 1:37 ` Nick Piggin
2007-08-16 19:23 ` Chris Snook
2007-08-17 0:04 ` Herbert Xu
2007-08-14 22:38 ` [patch 2/2] x86_64: " Sebastian Siewior
-- strict thread matches above, loose matches on Subject: below --
2007-08-15 20:54 [patch 0/2] use asm() for atomic_{read|set} (shot 2) Sebastian Siewior
2007-08-15 20:54 ` [patch 1/2] i386: use asm() like the other atomic operations already do Sebastian Siewior
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