Building A 96-Core Ubuntu ARM Solar-Powered Cluster

Last week I shared results from the Phoronix 12-core ARM Linux mini cluster that was constructed out of six PandaBoard ES development boards. Over the weekend, a 96-core ARM cluster succeeded this build. While packing nearly 100 cores and running Ubuntu Linux, the power consumption was just a bit more than 200 Watts. This array of nearly 100 processor cores was even powered up by a solar panel.

This past weekend I was out at the Massachusetts Institute of Technology (MIT) where this build took place. A massive ARM build out has been in the plans for a few months and to even get it running off a solar panel. The build was a success and by Sunday, the goals were realized.

Due to my past ARM Linux benchmarking on Phoronix that they have followed, their use of the Phoronix Test Suite, and my experience with Linux benchmarking and performance testing in general, I was invited over to MIT to help with this 96-core ARM build after having collaborated with them for a few months. This cluster / super-computer was built around 48 PandaBoards.

The bulk of the PandaBoards were not the ES model (I brought my collection of PandaBoard ES models as back-ups for the PandaBoard nodes that failed), but just the vanilla model. The non-ES model packs a Texas Instruments OMAP4430 with a dual-core 1.0GHz dual-core Cortex-A9 processor. The GPU and CPU of the PandaBoard ES with its OMAP4460 are at higher clock speeds, but aside from that it is very similar to the OMAP4430 model.

For maximum density and to make it easier to transport, the PandaBoards ended up being stacked vertically. The enclosure for the 48 PandaBoards was an industrial trashcan. Rather than using AC adapters, the PandaBoards were running off a USB power source. The power consumption on the original PandaBoard is similar to that of the PandaBoard ES or perhaps slightly lower when using the more efficient USB power source. My PandaBoard ES testing usually indicates about a 3 Watt idle per board, 5 Watt under load, or 6 Watts under extreme load. This MIT 96-core cluster would idle at just under 170 Watts and for the loads we hit it with over the weekend usually would just go a bit above 200 Watts.