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From: Ulrich Drepper <drepper@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
	"Randy.Dunlap" <rdunlap@xenotime.net>,
	akpm@osdl.org, linux-kernel@vger.kernel.org,
	libc-alpha@sourceware.org
Subject: Re: [PATCH] Use uname not sysctl to get the kernel revision
Date: Wed, 12 Jul 2006 09:50:06 -0700	[thread overview]
Message-ID: <44B5283E.7090806@redhat.com> (raw)
In-Reply-To: <m1irm2bxk3.fsf_-_@ebiederm.dsl.xmission.com>

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Eric W. Biederman wrote:
> But uname is noticeably faster than sysctl and uname is more portable
> across linux flavors.  So updating the glibc pthread code to use
> uname looks like the right way to implement is_smp_system. 

This is (was?) not the universal through.  We used uname at some point
but then I did some profiling and sysctl turned out to be faster.

If the reverse is true now I can certainly look into changing this but
the evidence and ideally has to be there.  The simplicity of the uname
code should mean that it's faster.

In a year or two I'll remove the test anyway.  By then there will likely
not be any UP kernels on reasonable machines anymore and I can drop all
the conditional code.

-- 
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖


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  reply	other threads:[~2006-07-12 16:49 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-10 22:39 [PATCH] sysctl: Document that sys_sysctl will be removed Eric W. Biederman
2006-07-10 22:50 ` Randy.Dunlap
2006-07-11  4:10   ` Eric W. Biederman
2006-07-11  7:07     ` Arjan van de Ven
2006-07-12 16:25       ` [PATCH] Use uname not sysctl to get the kernel revision Eric W. Biederman
2006-07-12 16:50         ` Ulrich Drepper [this message]
2006-07-12 17:42           ` Eric W. Biederman
2006-07-12 23:24             ` Theodore Tso
2006-07-12 23:31               ` Andi Kleen
2006-07-13  0:12                 ` Theodore Tso
2006-07-13  2:33                   ` Eric W. Biederman
2006-07-13 12:15                   ` Andi Kleen
2006-07-12 23:44               ` Steve Munroe
2006-07-14 18:49                 ` Benjamin Herrenschmidt
2006-07-14 19:09                   ` Andi Kleen
2006-07-13  0:19               ` Eric W. Biederman
2006-07-12 18:44           ` Roland McGrath
2006-07-12 19:33             ` Ulrich Drepper
2006-07-12 19:53               ` Jakub Jelinek
2006-07-12 20:09                 ` H. Peter Anvin
2006-07-12 21:23                   ` Eric W. Biederman
2006-07-12 21:29                     ` Arjan van de Ven
2006-07-12 21:56                       ` Eric W. Biederman
2006-07-12 22:01                         ` Arjan van de Ven
2006-07-12 22:02                           ` H. Peter Anvin
2006-07-12 22:26                             ` Eric W. Biederman
2006-07-12 22:31                               ` H. Peter Anvin
2006-07-12 23:07                               ` Alan Cox
2006-07-12 23:19                                 ` H. Peter Anvin
2006-07-13 11:15                                   ` Alan Cox
2006-07-14 18:45                                 ` Benjamin Herrenschmidt
2006-07-14 19:11                                   ` H. Peter Anvin
2006-07-12 21:29                     ` H. Peter Anvin
2006-07-12 21:33                     ` Michael Tokarev
2006-07-13  5:17                     ` Ulrich Drepper
2006-07-13  6:27                       ` Ian Wienand
2006-07-13 14:39                       ` Eric W. Biederman
2006-07-13 15:05                         ` Arjan van de Ven
  -- strict thread matches above, loose matches on Subject: below --
2006-07-13  5:00 Albert Cahalan
2006-07-13  5:42 ` H. Peter Anvin
2006-07-13  6:09   ` Albert Cahalan
2006-07-13  6:13     ` Albert Cahalan
2006-07-13  6:38 ` Eric W. Biederman
2006-07-13 16:15   ` Albert Cahalan
2006-07-13 16:53     ` Eric W. Biederman
2006-07-13 17:06       ` Albert Cahalan
2006-07-13 15:20 ` Eric W. Biederman

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