[petsc-dev] MatMult on Summit

[Jed Brown]

Karl Rupp <rupp at iue.tuwien.ac.at> writes:

>> I wonder if the single-node latency bugs on AC922 are related to these
>> weird performance results.
>> 
>> https://docs.google.com/spreadsheets/d/1amFJIbpvs9oJcUc-WntsFHO_C0LE7xFJeor-oElt0LY/edit#gid=0
>> 
>
> Thanks for these numbers!
> Intra-Node > Inter-Node is indeed weird. I haven't observed such an 
> inversion before.

As far as I know, it's been there since the machines were deployed
despite obviously being a bug.  I know people at LLNL regard it as a
bug, but it has not been their top priority (presumably at least in part
because applications have not clearly expressed the impact of latency
regressions on their science).