[Pw_forum] difference between cpu time and wall time

[mohammed shambakey]

Ok, thanks.

I have a test that uses 96 physical cores WITHOUT thread. The output
recorded time is:

PWSCF        :     0h57m CPU        1h44m WALL

By running the same experiement with 96 physical cores and 2 threads per
core (total 192 cores). The output recorded time is:

PWSCF        :     1h41m CPU        1h39m WALL

CPU time in case of 2 threads is larger than NO threads, but wall time in
case of 2 threads is less than NO threads. So, I just wonder about the
meaning of each criteria? and which one I should consider for performance
comparison?

Regards

On Wed, Sep 30, 2015 at 12:42 PM, Paolo Giannozzi <p.giannozzi at gmail.com>
wrote:

> Yes: "wall time" = "what the clock on the wall shows"
>
> Paolo
>
> On Wed, Sep 30, 2015 at 12:29 PM, mohammed shambakey <shambakey1 at gmail.com
> > wrote:
>
>> Hi
>>
>> In output files, there is cpu time and wall time. Does wall time include
>> cpu time plus any time for transer, I/O, and any thing else?
>>
>> Regards
>>
>> --
>> Mohammed
>>
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>>
>
>
>
> --
> Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
> _______________________________________________
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> http://pwscf.org/mailman/listinfo/pw_forum
>



-- 
Mohammed
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