From: Paul Jackson <pj@sgi.com>
To: Ulrich Drepper <drepper@redhat.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
ego@in.ibm.com, dipankar@in.ibm.com
Subject: Re: getting processor numbers
Date: Tue, 3 Apr 2007 20:04:09 -0700 [thread overview]
Message-ID: <20070403200409.d632bef3.pj@sgi.com> (raw)
In-Reply-To: <4612DCA2.2090400@redhat.com>
Ulrich wrote:
> For sysconf() we still need better support. Maybe now somebody will
> step up and say they need faster sysconf as well.
That won't be me ;).
For any kernel compiled with CONFIG_CPUSETS (which includes the major
distros I am aware of), one can just count the bits in the top cpusets
'cpus' value, which is always the online CPU mask. Even if your user
level software is making no conscious use of cpusets, this works, for
kernels so configured.
If there is someone who needs both a faster sysconf
(_SC_NPROCESSORS_CONF) and a kernel without CPUSETS configured, then
they will have to speak up for themselves.
--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.925.600.0401
next prev parent reply other threads:[~2007-04-04 3:04 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-03 16:54 getting processor numbers Ulrich Drepper
2007-04-03 17:30 ` linux-os (Dick Johnson)
2007-04-03 17:37 ` Ulrich Drepper
2007-04-03 17:56 ` Dr. David Alan Gilbert
2007-04-03 18:11 ` Andi Kleen
2007-04-03 17:17 ` Ulrich Drepper
2007-04-03 17:22 ` Alan Cox
2007-04-03 17:30 ` Andi Kleen
2007-04-03 20:24 ` Jeremy Fitzhardinge
2007-04-03 17:27 ` Andi Kleen
2007-04-03 17:30 ` Ulrich Drepper
2007-04-03 17:35 ` Andi Kleen
2007-04-03 17:45 ` Ulrich Drepper
2007-04-03 17:58 ` Andi Kleen
2007-04-03 18:05 ` Ulrich Drepper
2007-04-03 18:11 ` Andi Kleen
2007-04-03 18:21 ` Ulrich Drepper
2007-04-03 17:44 ` Siddha, Suresh B
2007-04-03 17:59 ` Ulrich Drepper
2007-04-03 19:40 ` Jakub Jelinek
2007-04-03 20:13 ` Ingo Oeser
2007-04-03 23:38 ` J.A. Magallón
2007-04-03 19:55 ` Ulrich Drepper
2007-04-03 20:13 ` Siddha, Suresh B
2007-04-03 20:19 ` Ulrich Drepper
2007-04-03 20:32 ` Eric Dumazet
2007-04-03 20:20 ` Nathan Lynch
2007-04-03 19:15 ` Davide Libenzi
2007-04-03 19:32 ` Ulrich Drepper
2007-04-04 0:31 ` H. Peter Anvin
2007-04-04 0:35 ` Jeremy Fitzhardinge
2007-04-04 0:38 ` H. Peter Anvin
2007-04-04 5:09 ` Eric Dumazet
2007-04-04 5:16 ` H. Peter Anvin
2007-04-04 5:22 ` Jeremy Fitzhardinge
2007-04-04 5:40 ` H. Peter Anvin
2007-04-04 5:46 ` Eric Dumazet
2007-04-04 5:29 ` Eric Dumazet
2007-04-03 20:16 ` Andrew Morton
[not found] ` <4612BB89.8040102@redhat.com>
[not found] ` <20070403141348.9bcdb13e.akpm@linux-foundation.org>
2007-04-03 22:13 ` Ulrich Drepper
2007-04-03 22:48 ` Andrew Morton
2007-04-03 23:00 ` Ulrich Drepper
2007-04-03 23:23 ` Andrew Morton
2007-04-03 23:54 ` Ulrich Drepper
2007-04-04 2:55 ` Paul Jackson
2007-04-04 8:39 ` Oleg Nesterov
2007-04-04 9:39 ` Ingo Molnar
2007-04-04 8:57 ` Oleg Nesterov
2007-04-04 10:01 ` Ingo Molnar
2007-04-04 2:58 ` Paul Jackson
2007-04-04 3:04 ` Paul Jackson [this message]
2007-04-04 2:52 ` Paul Jackson
2007-04-04 2:04 ` Paul Jackson
2007-04-04 6:47 ` Jakub Jelinek
2007-04-04 7:02 ` Paul Jackson
2007-04-04 14:51 ` Cliff Wickman
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