Calxeda's ARM server tested

Software Support

Calxeda supports Ubuntu and Fedora, though any distribution based on the (32-bit) ARM Linux kernel should in theory be able to run on the EnergyCore SoCs. As for availability, there are already prebuilt Highbank kernel images available in the Ubuntu ARM repository and Calxeda has set up a PPA of its own to ease its kernel development.

The company has also joined Linaro—the non-profit organization aiming to bring the open source ecosystem to ARM SoCs.

The ARM Server CPU

A dual Xeon E5 or Opteron 6300 server has much more processing power than most of us need to run one server application. That is the reason why it is not uncommon to see 10, 20 or even more virtual machines running on top of them. Extremely large databases and HPC applications are the noticeable exceptions, but in general, server purchasers are rarely worried about whether or not the new server will be fast enough to run one application.

Returning to our Boston Viridis server, the whole idea behind the server is not to virtualize but to give each server application its own physical node. Each server node has one quad-core Cortex-A9 with 4MB of L2 cache and 4GB of RAM. With that being the case, the question "what can this server node cope with?" is a lot more relevant. We will show you a real world load further in this review, but we thought it would be good to first characterize the performance profile of the EnergyCore-1000 at 1.4GHz. We used four different benchmarks: Stream, 7z LZMA compression, 7z LZMA decompression, and make/gcc building and compiling.

We compare the ECX-1000 (quad-core, 3.8~5W, 40nm) with an Intel Atom 230 (1.6GHz single-core plus Hyper-Threading, 4W TDP, 45nm), Atom N450 (1.66GHz single-core + HTT, 5.5W TDP, 45nm), Atom N2800 (1.86GHz dual-core + HTT, 6.5W, 32nm), and an Intel Xeon E5-2650L (1.8-2.3GHz octal-core, 70W TDP, 32nm).

The best comparable Atom would be the Atom S1200, which is Intel's first micro-server chip. However the latter was not available to us yet, but we are actively trying to get Intel's latest Atom in house for testing. We will update our numbers as soon as we can get an Atom S1200 system. The Atom N2800 should be very close to the S1200, as it has the same architecture, L2 cache size, TDP, and runs at similar clockspeeds. The Atom N2800 supports DDR3-1066 while Centerton will support DDR3-1333, but we have reason to believe (see further) that this won't matter.

The Atom 230/330 and N450 are old 45nm chips (2008-2010). And before you think using the Atom 230 and N450 is useless: the Atom architecture has not changed for years. Intel has lowered the power consumption, increased the clockspeed, and integrated a (slightly) faster memory controller, but essentially the Atom 230 has the same core as the latest Atom N2000. I quote Anand as he puts it succinctly: "Atom is in dire need of an architecture update (something we'll get in 2013)."

So for now, the Atom 230 and N450 numbers give us a good way to evaluate how the improvements in the "uncore" impact server performance. It is also interesting to see where the ECX-1000 lands. Does it outperform the N2800, or is just barely above the older Atom cores?