Arm photon Torpedoes. Prepare to fire on the Klingon Warbirds.

scottcschweitzer networking

Is an unforgettable quote from Captain James T. Kirk of the starship Enterprise that still sends chills down my spine. Unfortunately, we need to take a break this week from Machine Vision Acceleration (MVA), to let the ink dry on a few things. So instead we’re going to explore tools by answering one simple question, how strong is your optical signal? From mythical Photon Torpedoes to real life photonic communication mankind defines itself by its tools. How good are the 10GbE tools your NIC vendor provides to configure & diagnose the status of your adapter and optics, and are they free? 

Yesterday I had the pleasure of visiting a DoD customer of mine in DC whom I’ve been selling 10GbE NICs to since early 2006. They asked what appeared to be a very simple question: “How can we tell the optical signal strength coming into your NIC?” Their servers are installed in extremely remote collocation facilities. Clearly, this is a reasonable question, but in my nearly eight years of selling 10GbE, it’s one I’ve never been asked. I said I’m sure we have something that provides that info, perhaps “ethtool -S” might do it, I’ll look into it. It turns out we have a tool called “mdio_rw” that we provide with our free Myri-10G Adapter Tool Kit. Today I had a chance to install the toolkit and test it out. There are over 20 tools in this digital bucket, most are diagnostic or for extreme setup, meaning they aren’t for the faint of heart. Here is how you install the toolkit on Linux if you’re a windows user visit the above link for those details.

# gunzip -c myri-tools-linux.tar.gz | tar xvf – 
# cd myri-tools-1.26-linux/bin
Then to see the receive power, the amount of light arriving into the adapter on the first 10GbE port, you can issue the command:

# mdio_rw -b 0 | grep RX 

RX power = 0.6199 mW

This is the actual output from one of my test systems. The command returns another dozen parameters, some pretty interesting, but I’ll leave that to you to explore. 

Many of the 20+ tools in this package can be used to change how the adapter works by altering settings, upgrading the firmware, or performing deep diagnostics, all of these should be used with great caution. Here are several other interesting ones that rookies like I can play around with to gather useful information:


myri_info – Returns a number of hardware statistics on the adapter & PCIe bus. 
myri_pcie_conf – This confirms the PCIe payload sizes of the adapter and the system chipsets.
myrige-test.sh – Performs an adapter loopback self-test.

There is more to the loopback self-test, which you can read about in this link. 
So the next time you buy a 10GbE adapter check first to see what tools your vendor provides to help answer any questions you might have, diagnose any issues that may arise or allow you to further tune or configure your system’s performance. Also are the tools free, and easy to install and use? You may be surprised at what you might learn. 

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