Ubuntu Server 20.04 CPU Security Mitigation Performance Impact

With the exception of the low-end Xeon E3-1275 v6 Kabylake system being rather resource constrained and overloaded by BlogBench, the more powerful server platforms where there was less of an I/O bottleneck showed a few percentage hit from the default mitigations on Ubuntu 20.04. This included the Xeon Cascade Lake Refresh and AMD Rome platforms with their respective levels of hardware mitigation baked into the chips.

With Sockeperf for stressing the Linux networking socket interface, the Haswell, Kabylake, and Skylake servers all showed hefty hits to their performance from the default mitigation. But the Cascade Lake Refresh and Rome platforms with their hardware mitigations led to no measurable difference in this comparison.

But when looking at the socket latency, all of the tested platforms did show higher latency from the default mitigations.

The networking overhead with the default mitigations on the older chips also translated to some hits with the iPerf networking benchmark.