Re: cores vs hyperthreads

On 09/08/2016 07:14 AM, Jon LaBadie wrote:
> On Wed, Sep 07, 2016 at 09:08:06PM -0500, Bill Wilson wrote:
>> On Wed, 07 Sep 2016 21:41:13 -0400
>> Jon LaBadie <[email protected]> wrote:
>>
>>> My 6 core processor shows up as 12 CPUs due to
>>> Intel's HyperThreading.  Is there a way to tell
>>> in gkrellm, which are the hyperthread displays?
>>>
>>
>> Gkrellm gets data from /proc/stat and hyperthreaded CPUs aren't
>> differentiated there, so you can't tell from inside of gkrellm.  If you
>> look at /proc/cpuinfo I think you will find they are paired sequentially.
>> That is processor 0 and processor 1 will probably have the same core id and
>> so on,
>>
> Thanks,
> in my case processor 0&6, 1&7, etc are core id paired.
> 
> jon
> 

Hi Jon,

Easier than reading /proc/cpuinfo, the hwloc tool/lib can give you the
topology of your processor:
https://www.open-mpi.org/projects/hwloc/

Best regards,
Pierre