High Performance Computing Networking

MPI newbie: Building MPI applications

In a previous post, I gave some (very) general requirements for how to setup / install an MPI installation. This is post #2 in the series: now that you’ve got a shiny new computational cluster, and you’ve got one or more MPI implementations installed, I’ll talk about how to build, compile, and link applications that […]

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, wrote this IMUDI paper about the interface (IMUDI […]

EuroMPI’13 Cisco slides: UCS, Nexus, usNIC

A few people asked me to post the slides that I just presented in the Cisco vendor session at EuroMPI’13.  In short, I gave a brief overview of our servers and switches, and then some technical details of how we use SR-IOV in our usNIC, etc. Here’s the slides:

usNIC released!

I’m excited to announce that Cisco has just released usNIC as a feature of the UCS C-Series Rack Servers product line. usNIC is available since the release 1.5(2) of the Cisco UCS C-Series Integrated Management Controller.

Why is SR-IOV relevant in the HPC world ?

One feature of the usNIC ultra-low latency Ethernet solution for the UCS Cisco VIC that we think is interesting is the fact that it is based on SR-IOV. What is SR-IOV, and why is it relevant in the HPC world? SR-IOV (Single Root I/O Virtualization) is commonly used in the server virtualization world. The most […]

MPI newbie: Requirements and installation of an MPI

I often get questions from those who are just starting with MPI; they want to know common things such as: How to install / setup an MPI implementation How to compile their MPI applications How to run their MPI applications How to learn more about MPI This will be the first blog entry of several […]

Short message latency and NUMA effects

I’ve previously written a bunch about the effects of location, Location, LOCATION! on MPI applications. Here’s another subtle NUMA effect that a well-tuned MPI implementation can hide from you: intelligently distributing traffic between multiple network interfaces. Yeah, yeah, most MPI implementations have had so-called “multi-rail” support for a long time (i.e., using multiple network interfaces […]

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?” I can think of (at least) […]

Ultra low latency Ethernet (UCS “usNIC”): questions and answers

I have previously written a few details about our upcoming ultra low latency solution for High Performance Computing (HPC).  Since my last blog post, a few of you sent me emails asking for more technical details about it. So let’s just put it all out there.