[CentOS] processor affinity

[Marcelo M. Garcia]

John Doe wrote:
> From: Simon Billis <simon at houxou.com>
>> To: CentOS mailing list <centos at centos.org>
>> Sent: Thu, February 18, 2010 11:25:41 AM
>> Subject: Re: [CentOS] processor affinity
>>
>> Adam Grossman sent a missive on 2010-02-17:
>>
>>> On Wed, 2010-02-17 at 13:26 -0500, Adam Grossman wrote:
>>>> On Wed, 2010-02-17 at 18:17 +0000, Simon Billis wrote:
>>>>> Adam Grossman sent a missive on 2010-02-17:
>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> i am running CentOS 5.4.  i have a requirement where i need to have 1
>>>>>> application have a single processor all to its self, and the rest of
>>>>>> the system run on the other processors.  "taskman" lets me bind the
>>>>>> process to a processor(s), but it does not make it exclusive.   Is
>>>>>> this possible to do? i have even tried mucking around with the
>>>>>> rc.sysinit, but to no avail.
>>>>>>
>>>>>> thank you very much,
>>>>> Have you considered running through the pids of the all tasks and then
>>>>> using taskset to change their affinities. You could also change all
>>>>> the init scripts to invoke the process using something like "taskset
>>>>> -p [mask] [pid]" and limit the mask to only the first few CPU's that
>>>>> you want them to have access to.
>>>>>
>>>> that's probably a good idea.  have it be the last service that runs
>>>> which moves everything to the processors i want.  i am going to give
>>>> that an try.
>>> i was asked to do this for increased performance.  but does centos
>>> have any SMP load balancing which would probably work better then
>>> manually doing load balancing?
>>>
>> Linux does have cpu load balancing to maximise performance, but performance
>> of an application/process relies on many things. You may have to tune the
>> system for that particular application and also reduce the number of other
>> processes running to maximise the performance. Application tuning may also
>> be required for maximum performance gains.
> 
> What about renicing processes...?
> 
> JD
> 
> 
Hi

I don't this helps, but in the BIOS of Dell Precision I have to option 
of choose the memory management to be SMP or NUMA, the default is SMP. 
If you choose to NUMA than you have a better affinity.

Regards

mg.