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From: "MacCana, Mike" <mike.maccana@credit-suisse.com>
To: linux-numa@vger.kernel.org
Subject: Possible man numactl error?
Date: Thu, 11 Feb 2010 14:26:14 -0000	[thread overview]
Message-ID: <5608FA8A997F1A46B7E985494F8478DD079309DA@ELON17P32003A.csfb.cs-group.com> (raw)

Hi NUMA folks,
 
I've spotted what appears to be an inconsistency between man numactl and
/proc & /sys.
 
       --physcpubind=cpus, -C cpus
              Only  execute  process  on cpus.  This accepts physical
cpu numbers as shown in the processor fields of /proc/cpuinfo.
 
However the processor field of /proc/cpuinfo refers to logical
processors (ie, run queues), not physical ones. Eg:
 
$ grep processor /proc/cpuinfo 
processor       : 0
processor       : 1
... 
Compared to:

$ cat /sys/devices/system/cpu/cpu0/topology/physical_package_id 
0

$ cat /sys/devices/system/cpu/cpu1/topology/physical_package_id 
0

I.e., CPUs 0 and 1 are clearly on the same physical package. 

Futhermore, physical CPU numbers are shown with the string 'physical id'
not 'processor' in /proc/cpuinfo. 
 
Is the numactl man page incorrect, or am I missing something? Does -C
work on physical CPUs but just have bad documentation, or does it mean
logical CPUs per the documentation?
 
Thanks,
 
Mike

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next             reply	other threads:[~2010-02-11 14:26 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-11 14:26 MacCana, Mike [this message]
2010-02-11 14:40 ` Possible man numactl error? Andi Kleen
2010-02-11 14:49   ` MacCana, Mike

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