[petsc-users] Pthread support

[Jed Brown]

On Mon, Jul 23, 2012 at 9:08 PM, Alexander Goncharov <alexvg77 at gmail.com>wrote:

> Hello!
>
> I have a question about pthread support in PETSC. I could not find it in
> the development version. Is it going to be supported in the new release?
>
> The reason I tried development version is because in petsc-3.3 compiled
> with pthreadclasses=1 all jobs would be sent to one core, if I start
> executables separately. Same for MPI, mpirun -np 4 would show up as 4
> processes with 25% CPU usage each, in the "top" output. Without
> pthreadclasses all is ok. I would have processes with each utilizing
> separate core at 100%. Have you come across such a behavior?
>

Sounds like an affinity problem. When running with multiple MPI processes
and threads, you generally have to specify the number of threads manually.

The threading code is in the process of being overhauled to a cleaner and
more flexible design. It's not ready for use yet, but should be in a couple
months.
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