[Difx-users] Machines file using mpich

[Gill, Ajaypal]

Hi Adam,

Okay, sounds good. Thank you very much for the help!

Best,
Ajay

On Mon, Jun 11, 2018 at 2:43 AM, Adam Deller <adeller at astro.swin.edu.au>
wrote:

> Hi Ajay,
>
> I'm not aware of a way to control the number of threads on a per-process
> basis in mpich.  You can (and should) set the phread worker processes
> spawned by each Core process in the .threads file.  The first entry in the
> .threads file corresponds to the first Core process, the second to the
> second Core process, and so on.  Those are the only significant consumers
> of CPU, and you would normally set that number to 1 fewer than the number
> of CPU cores you have available (so that last core is available to do the
> sending and receiving etc).  Actually there are two other threads running
> on the Core process (one doing only communication, one doing the small
> amount of other non-communication housekeeping that is needed) but they can
> happily co-exist on a single CPU core.
>
> For the FxManager and Datastream processes, there's no way to limit the
> number of CPU cores they use, but they are not very compute intensive
> except in special corner cases anyway.
>
> Cheers,
> Adam
>
> On 11 June 2018 at 14:37, Gill, Ajaypal <ajaypal.gill at cfa.harvard.edu>
> wrote:
>
>> Hi,
>>
>> I understand that when using openmpi, it's possible for instance to set
>> the .machines file as follows to select the number of cores to use per node:
>>
>> node1 slots=10 #fx manager
>>
>> node2 slots=10 #datastream1
>>
>> node3 slots=10 #datastream2
>>
>> node4 slots=10 #datastream3
>>
>> node5 slots=20 #core
>>
>> However, I see that this format doesn't work when using mpich. Is there
>> any similar way to select the number of cores per node using mpich?
>>
>> Best regards,
>>
>> Ajay Gill (summer student)
>>
>>
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>>
>
>
> --
> !=============================================================!
> Dr. Adam Deller
> ARC Future Fellow, Senior Lecturer
> Centre for Astrophysics & Supercomputing
> Swinburne University of Technology
> John St, Hawthorn VIC 3122 Australia
> phone: +61 3 9214 5307
> fax: +61 3 9214 8797
>
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> !=============================================================!
>



-- 
Best,
Ajay
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