Assessing Cavium's ThunderX2: The Arm Server Dream Realized At Last

Benchmark Configuration and Methodology

For our look at the ThunderX2, all of our testing was conducted on Ubuntu Server 17.10, Linux kernel 4.13 64 bit. Normally we would use an LTS version, but since the Cavium shipped with that Ubuntu version, we did not want to take any unnecessary risks by changing the OS. The compiler that ships with this distribution is GCC 7.2.

Unfortunately however, our AMD EPYC system has missed the deadline for this article. We ran into problems with that system right up to press time and are still debugging the matter. But in short, the system did not perform well after we performed a kernel upgrade.

Finally, you will notice that the DRAM capacity varies among our server configurations. The reason is simple: Intel's system has 6 memory channels, while Cavium's ThunderX2 has 8 memory channels.

Gigabyte - Cavium "Saber"

Intel's Xeon "Purley" Server – S2P2SY3Q (2U Chassis)

The typical BIOS settings can be seen below. I should also note that we have both hyperthreading and Intel's virtualization technology enabled.

Other Notes

Both servers are fed by a standard European 230V (16 Amps max.) power line. The room temperature is monitored and kept at 23°C by our Airwell CRACs.

Energy Consumption

One thing that concerned us was the fact that the Gigabyte "Saber" system consumed 500W while simply running Linux (so mostly idle). Under load however the system consumed around 800W, which is in line with our expectations, as we have two 180W TDP chips inside. So as is typically the case for early test systems, we are not able to do any accurate power comparisons.

In fact, Cavium claims that the actual systems from HP, Gigabyte and others will be far more power efficient. The "Sabre" testing system we received had several power management problems: immature fan management firmware, a BMC bug, and an oversized (1600W) PSU.