[mpich-discuss] MPI process binding on SunOS systems

Wed Apr 1 12:34:51 CDT 2015

Hi Pavan,
thank you for your answer.
I get this output:

larcher at na75:> HYDRA_TOPO_DEBUG=1  mpiexec -n 8 -bind-to hwthread -map-by
core /bin/true | sort
process 0 binding: 1 0 0 0 0 0 0 0
process 1 binding: 0 1 0 0 0 0 0 0
process 2 binding: 0 0 1 0 0 0 0 0
process 3 binding: 0 0 0 1 0 0 0 0
process 4 binding: 0 0 0 0 1 0 0 0
process 5 binding: 0 0 0 0 0 1 0 0
process 6 binding: 0 0 0 0 0 0 1 0
process 7 binding: 0 0 0 0 0 0 0 1

larcher at na75:> HYDRA_TOPO_DEBUG=1  mpiexec -n 4 -bind-to hwthread -map-by
core /bin/true | sort
process 0 binding: 1 0 0 0 0 0 0 0
process 1 binding: 0 1 0 0 0 0 0 0
process 2 binding: 0 0 1 0 0 0 0 0
process 3 binding: 0 0 0 1 0 0 0 0

which is exactly what I need, thank you !
Also passing -bind-to core:1 is suitable.
Best,

Aurelien

On Wed, Apr 1, 2015 at 7:28 PM, Balaji, Pavan <balaji at anl.gov> wrote:

>
> Try this:
>
> HYDRA_TOPO_DEBUG=1  mpiexec -n 8 -bind-to hwthread -map-by core /bin/true
> | sort
>
>   -- Pavan
>
> > On Apr 1, 2015, at 12:26 PM, Balaji, Pavan <balaji at anl.gov> wrote:
> >
> >
> > This is not linux specific.  It's following whatever order the OS gives
> it.  You might want to look at the -map-by option for better controlling
> the processes in the way you are looking for.
> >
> >  -- Pavan
> >
> >> On Apr 1, 2015, at 11:47 AM, Aurélien Larcher <
> aurelien.larcher at gmail.com> wrote:
> >>
> >> Hi Rajeev,
> >> thank you for the pointer, actually this page leads me to another
> question.
> >> What is exactly the policy for binding by hwthreads ?
> >>
> >> I can see that:
> >>
> >> larcher at na75:> HYDRA_TOPO_DEBUG=1  mpiexec -n 8 -bind-to hwthread
> /bin/true | sort
> >> process 0 binding: 1 0 0 0 0 0 0 0
> >> process 1 binding: 0 0 0 0 1 0 0 0
> >> process 2 binding: 0 1 0 0 0 0 0 0
> >> process 3 binding: 0 0 0 0 0 1 0 0
> >> process 4 binding: 0 0 1 0 0 0 0 0
> >> process 5 binding: 0 0 0 0 0 0 1 0
> >> process 6 binding: 0 0 0 1 0 0 0 0
> >> process 7 binding: 0 0 0 0 0 0 0 1
> >>
> >> Which seems unfortunate because since the processor is a quad core with
> hyperthreading the same physical core will get the first two threads.
> >>
> >> larcher at na75:> psrinfo -pv
> >> The physical processor has 4 cores and 8 virtual processors (0-7)
> >>  The core has 2 virtual processors (0 4)
> >>  The core has 2 virtual processors (1 5)
> >>  The core has 2 virtual processors (2 6)
> >>  The core has 2 virtual processors (3 7)
> >>    x86 (GenuineIntel 206A7 family 6 model 42 step 7 clock 3392 MHz)
> >>      Intel(r) Core(tm) i7-2600 CPU @ 3.40GHz
> >>
> >>
> >> This is confirmed by:
> >>
> >> HYDRA_TOPO_DEBUG=1  mpiexec -n 4 -bind-to hwthread /bin/true | sort
> >> process 0 binding: 1 0 0 0 0 0 0 0
> >> process 1 binding: 0 0 0 0 1 0 0 0
> >> process 2 binding: 0 1 0 0 0 0 0 0
> >> process 3 binding: 0 0 0 0 0 1 0 0
> >>
> >> Is it due to a Linux-specific numbering of logical cores ?
> >>
> >> Thank you,
> >>
> >> Aurelien
> >>
> >>
> >>
> >>
> >> On Wed, Apr 1, 2015 at 6:18 PM, Thakur, Rajeev <thakur at mcs.anl.gov>
> wrote:
> >> Yes, see
> https://wiki.mpich.org/mpich/index.php/Using_the_Hydra_Process_Manager#Process-core_Binding
> >>
> >> Rajeev
> >>
> >>
> >> On Apr 1, 2015, at 11:14 AM, Aurélien Larcher <
> aurelien.larcher at gmail.com>
> >> wrote:
> >>
> >>> Hi,
> >>> running parallel code on my workstation (with OpenIndiana) I
> discovered that MPI processes were migrated on a regular basis from one
> core to another.
> >>>
> >>> On SunOS systems the command 'pbind' allows binding a process to a
> specific core.
> >>> So I am wondering if binding automatically each process to the next
> available core is supported directly from MPICH ?
> >>>
> >>> Best regards
> >>>
> >>> Aurelien
> >>>
> >>> --
> >>>
> -------------------------------------------------------------------------------
> >>> LARCHER Aurélien          | KTH, School of Computer Science and
> Communication
> >>> Work: +46 (0) 8 790 71 42 | Lindstedtsvägen 5, Plan 4, 100 44
> Stockholm, SWEDEN
> >>>
> -------------------------------------------------------------------------------
> >>> _______________________________________________
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> >>
> >> _______________________________________________
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> >>
> >>
> >> --
> >>
> -------------------------------------------------------------------------------
> >> LARCHER Aurélien          | KTH, School of Computer Science and
> Communication
> >> Work: +46 (0) 8 790 71 42 | Lindstedtsvägen 5, Plan 4, 100 44
> Stockholm, SWEDEN
> >>
> -------------------------------------------------------------------------------
> >> _______________________________________________
> >> discuss mailing list     discuss at mpich.org
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> >
> > --
> > Pavan Balaji  ✉️
> > http://www.mcs.anl.gov/~balaji
> >
> > _______________________________________________
> > discuss mailing list     discuss at mpich.org
> > To manage subscription options or unsubscribe:
> > https://lists.mpich.org/mailman/listinfo/discuss
>
> --
> Pavan Balaji  ✉️
> http://www.mcs.anl.gov/~balaji
>
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-- 
-------------------------------------------------------------------------------
LARCHER Aurélien          | KTH, School of Computer Science and
Communication
Work: +46 (0) 8 790 71 42 | Lindstedtsvägen 5, Plan 4, 100 44 Stockholm,
SWEDEN
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