process affinity

Process affinity: Hop on the bus, Gus!

Today’s blog post is written by Joshua Ladd, Open MPI developer and HPC Algorithms Engineer at Mellanox Technologies. At some point in the process of pondering this blog post I noticed that my subconscious had, much to my annoyance, registered a snippet of the chorus to Paul Simon’s time…

EuroMPI’13 Cisco slides: Open MPI Process Affinity User Interface

The slides below are from my presentation at EuroMPI’13 about Open MPI’s flexible process affinity interface (in OMPI 1.7.2 and later).  I described this system in a prior blog entries (one, two, three), but many people keep asking me about it. Josh Hursey from U. Wisconsin, LaCrosse, wr…

How many network links do you have for MPI traffic?

If you’re a bargain basement HPC user, you might well scoff at the idea of having more than one network interface for your MPI traffic. “I’ve got (insert your favorite high bandwidth network name here)! That’s plenty to serve all my cores! Why would I need more than that?R…

Process and memory affinity: why do you care?

I’ve written about NUMA effects and process affinity on this blog lots of times in the past.  It’s a complex topic that has a lot of real-world affects on your MPI and HPC applications.  If you’re not using processor and memory affinity, you’re likely experiencing performance…