This meter represents your reputation at a 100% scale based on your level of participation on the site.
Find out more
In a prior blog post, I talked about latency analogies. I compared levels of latencies to your home, your neighborhood, a far-away neighborhood, and another city. I talked about these localities in terms of communication.
Let’s extend that analogy to talk about data locality.
This meter represents your reputation at a 100% scale based on your level of participation on the site.
Find out more
Multiple readers have told me that it is difficult for them to understand and/or visualize the effects of latency on their HPC applications, particularly in modern NUMA (non-uniform memory access) and NUNA (non-uniform network access) environments.
Let’s breaks down the different levels of latency in a typical modern server and network computing environments.
This meter represents your reputation at a 100% scale based on your level of participation on the site.
Find out more
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 degradation without even realizing it.
In short:
Tags: HPC, hwloc, mpi, NUMA, process affinity
This meter represents your reputation at a 100% scale based on your level of participation on the site.
Find out more
In my last post, I described the Simple mode of Open MPI v1.7′s process affinity system.
The Simple mode is actually quite flexible, and we anticipate that it will meet most users’ needs. However, some users will need more flexibility. That’s what the Expert mode is for.
Before jumping in to the Expert mode, though, let me describe two more features of the revamped v1.7 affinity system.
This meter represents your reputation at a 100% scale based on your level of participation on the site.
Find out more
In my last post, I mentioned that we just finished a complete revamp of the Open MPI process affinity system, and provided only a few details as to what we actually did.
I did link to a SVN commit message, but I’ll wager that few readers — if anyone — actually read it. :-)
Much of what is in the Open MPI v1.6.x series is the same as what Ralph Castain described in a prior blog post. I’ll describe below what we changed for the v1.7 series.
Tags: HPC, mpi, NUMA, Open MPI, process affinity