Re: [OMPI users] Do MPI calls ever sleep?

2010-07-27 Thread Barrett, Brian W
No, we really shouldn't. Having just fought with a program using usleep(1) which was behaving even worse, working around this particular inability of the Linux kernel development team to do something sane will only lead to more pain. There are no good options, so the best option is to not try

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-23 Thread Jeff Squyres
Should we replace OMPI's use of sched_yield() with usleep()? David -- could you try replacing the call to sched_yield() in opal/runtime/opal_progress.c (somewhere around line 220) to usleep(1) and see if that gives the behavior that you want (without twonking a /proc value)? You might also

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-22 Thread David Ronis
That did it. Thanks. David On Wed, 2010-07-21 at 15:29 -0500, Dave Goodell wrote: > On Jul 21, 2010, at 2:54 PM CDT, Jed Brown wrote: > > > On Wed, 21 Jul 2010 15:20:24 -0400, David Ronis > > wrote: > >> Hi Jed, > >> > >> Thanks for the reply and suggestion. I tried

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-21 Thread Dave Goodell
On Jul 21, 2010, at 2:54 PM CDT, Jed Brown wrote: > On Wed, 21 Jul 2010 15:20:24 -0400, David Ronis wrote: >> Hi Jed, >> >> Thanks for the reply and suggestion. I tried adding -mca >> yield_when_idle 1 (and later mpi_yield_when_idle 1 which is what >> ompi_info reports

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-21 Thread David Ronis
I'm running linux (slackware 12.2), openmpi 1.4.2 and fftw3 3.2.4. As to the planner always running in parallel, I suspect it isn't. It's trying to optimize the split up the fft computation between different codelets and different numbers of threads (including none). It tries something and

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-21 Thread Jed Brown
On Wed, 21 Jul 2010 15:20:24 -0400, David Ronis wrote: > Hi Jed, > > Thanks for the reply and suggestion. I tried adding -mca > yield_when_idle 1 (and later mpi_yield_when_idle 1 which is what > ompi_info reports the variable as) but it seems to have had 0 effect. > My

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-21 Thread David Ronis
Hi Jed, Thanks for the reply and suggestion. I tried adding -mca yield_when_idle 1 (and later mpi_yield_when_idle 1 which is what ompi_info reports the variable as) but it seems to have had 0 effect. My master goes into fftw planning routines for a minute or so (I see the threads being created),

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-21 Thread Douglas Guptill
Hi David: On Wed, Jul 21, 2010 at 02:10:53PM -0400, David Ronis wrote: > I've got a mpi program on an 8-core box that runs in a master-slave > mode. The slaves calculate something, pass data to the master, and > then call MPI_Bcast waiting for the master to update and return some > data via a

Re: [OMPI users] Do MPI calls ever sleep?

2010-07-21 Thread Jed Brown
On Wed, 21 Jul 2010 14:10:53 -0400, David Ronis wrote: > Is there another MPI routine that polls for data and then gives up its > time-slice? You're probably looking for the runtime option -mca yield_when_idle 1. This will slightly increase latency, but allows other

[OMPI users] Do MPI calls ever sleep?

2010-07-21 Thread David Ronis
I've got a mpi program on an 8-core box that runs in a master-slave mode. The slaves calculate something, pass data to the master, and then call MPI_Bcast waiting for the master to update and return some data via a MPI_Bcast originating on the master. One of the things the master does while