[petsc-dev] PETSc and threads

[Jed Brown]

"Nystrom, William David" <wdn at lanl.gov> writes:
> for PETSc thread support is because I have access to platforms where
> I think it could be very useful.

Why do you think that?

I encourage you to run tests with HPGMG-FV since Sam Williams has put a
great deal of effort into optimizing his threaded implementation.  Our
experience has been that flat MPI is faster on almost every machine we
tested for all problem sizes.  This coincides with work from others that
I believe did careful studies (including Intel engineers trying to
demonstrate threading success).

People have a lot of incentive to declare that MPI is not sufficient, so
many studies are declared complete when they produce data to support
that notion.  The true reason for such observations are often more
subtle, leading to a lot of misinformation and misdirected effort.

Let's strive to understand what we're doing instead of bumbling around
"just running shit" [1] until we confirm some preconceptions.


[1] Terminology courtesy Matt.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 818 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20150109/f7183ac4/attachment.sig>