Following up on this,
Indeed with a recent kernel the error message goes away.
The poor performance stays though (a few percent difference between 4.13
and 4.15rc5), and I'm at a loss as to whether it's related to MPI or not.
I see oddities such as locking the job to the first 12 cores yield 100%
Le 29/12/2017 à 23:15, Bill Broadley a écrit :
>
>
> Very interesting, I was running parallel finite element code and was seeing
> great performance compared to Intel in most cases, but on larger runs it was
> 20x
> slower. This would explain it.
>
> Do you know which commit, or anything else
Very interesting, I was running parallel finite element code and was seeing
great performance compared to Intel in most cases, but on larger runs it was 20x
slower. This would explain it.
Do you know which commit, or anything else that might help find any related
discussion? I tried a few
Hello
Make sure you use a very recent Linux kernel. There was a bug regarding L3
caches on 24-core Epyc processors which has been fixed in 4.14 and backported
in 4.13.x (and maybe in distro kernels too).
However, that would likely not cause huge performance difference unless your
application
I'm getting poor performance on OpenMPI tasks on a new AMD 7401P EPYC
server. I suspect hwloc providing a poor topology may have something to do
with it as I receive this warning below when creating a job.
Requested data files available at http://static.skysight.io/out.tgz
Cheers,
Matthew
