[mvapich-discuss] mpiexec/mvapich places processes on same cpu

[LEI CHAI]

Hi Joseph and Pasha,

Thank you for the suggestions. We already plan to add this feature to MVAPICH. It will be available in upcoming releases.

Lei


----- Original Message -----
From: "Pavel Shamis (Pasha)" <pasha at dev.mellanox.co.il>
Date: Sunday, January 20, 2008 4:45 am
Subject: Re: [mvapich-discuss] mpiexec/mvapich places processes on same cpu

> 
> > While we are at it - is there an actual way to assign with 
> either version to specific cores? We have a few large multinode 
> obs that can only use 4 out of 8 cores per node due to bus and 
> memory limitations. Is there a way to distribute the processes to 
> cores 1,2 and 5,6 ? ie to skip 0, and split the other 4 to 
> different chips? 
> >   
> Sounds good. As we have a option to specify HCA/port per rank it 
> may be 
> nice to have option to specify core. Should not be very 
> complicated to 
> implement. (I'm talking about mvapich1)
> Mvapich team, what do you think ?
> 
> Pasha
> > j
> >
> > ----- Original Message -----
> > From: LEI CHAI <chai.15 at osu.edu>
> > Date: Friday, January 18, 2008 7:00 pm
> > Subject: Re: [mvapich-discuss] mpiexec/mvapich places processes 
> on same cpu
> >
> >   
> >> Hi Joseph,
> >>
> >> Could you try disable the cpu affinity feature in 
> mvapich/mvapich2, e.g.
> >>
> >> mvapich2:
> >> $ mpiexec -n 4 -env MV2_ENABLE_AFFINITY 0 ./a.out
> >>
> >> or mvapich:
> >> $ mpirun_rsh -np 4 VIADEV_ENABLE_AFFINITY=0 ./a.out
> >>
> >> Thanks,
> >> Lei
> >>
> >>
> >> ----- Original Message -----
> >> From: Joseph Hargitai <joseph.hargitai at nyu.edu>
> >> Date: Friday, January 18, 2008 6:05 pm
> >> Subject: [mvapich-discuss] mpiexec/mvapich places processes on 
> same cpu
> >>
> >>     
> >>> hi all:
> >>>
> >>> While submitting two identical mpi jobs (-np 4) with 
> differetnt 
> >>> datasets for a dual socket quadocore node using two distinct 
> >>> pbs/mpiexec submission both jobs end up on the first 
> processor, 
> >>> such they use 4 cores of the first cpu, none of the second. 
> This 
> >>> results in 8 processes on cpu 1, with a load of about 8-9, 
> both 
> >>> jobs producing output okay, but obviously the choice would be 
> to 
> >>> have them on distinct cpus. 
> >>>
> >>> When one of these mpi jobs meet 4 others regular serial jobs 
> >>> submitted without mpiexec, all 8 cores are populated. 
> >>>
> >>> I did read on the group list about the first mpiexec session 
> being 
> >>> the master, but not reserving the first 4 cores such allowing 
> the 
> >>> possibility for the next mpi job to end up on the same cpu. 
> >>>
> >>> best,   
> >>> joseph
> >>> _______________________________________________
> >>> mvapich-discuss mailing list
> >>> mvapich-discuss at cse.ohio-state.edu
> >>> http://mail.cse.ohio-state.edu/mailman/listinfo/mvapich-discuss
> >>>
> >>>       
> > _______________________________________________
> > mvapich-discuss mailing list
> > mvapich-discuss at cse.ohio-state.edu
> > http://mail.cse.ohio-state.edu/mailman/listinfo/mvapich-discuss
> >
> >   
> 
> 
> -- 
> Pavel Shamis (Pasha)
> Mellanox Technologies
> 
>