ZombieLoad Mitigation Costs For Intel Haswell Xeon, Plus Overall Mitigation Impact

With tests over the past week following the disclosure of the Microarchitectural Data Sampling (MDS) vulnerabilities also known as "Zombieload", we've looked at the MDS mitigation costs (and now the overall Spectre/Meltdown/L1TF/MDS impact) for desktop CPUs, servers, and some laptop hardware. I've also begun doing some tests on older hardware, such as some Phoronix readers curious how well aging Intel Haswell CPUs are affected.

Coming up tomorrow I have some interesting mitigation cost comparison benchmarks for Intel Sandy/Ivy Bridge versus AMD Bulldozer era hardware while in this article are some Haswell Xeon results for reference using an Intel Xeon E5-1680 v3 server/workstation.

On this box, first up was looking exclusively at the mitigation impact for MDS/Zombieload:

MDS/ZombieLoad mitigations that landed last week along with the updated Intel CPU microcode slide the performance by about 9% across various benchmarks. That's in line with seeing 8~10% loss for some desktop CPUs while the 1st Gen Xeon Scalable Gold 6138 dual socket server tests from a few days ago saw just a 5% hit with MDS. All the individual benchmark results for this Haswell Xeon MDS comparison via this OpenBenchmarking.org result file.

When looking at the current costs of all mitigations to date combined, that's a 13% hit using the same set of benchmarks carried out for the recent Xeon/EPYC comparison a few days back. If also disabling Hyper Threading, it equates to about a 19% hit.

All those "mitigations=" benchmarks for this aging Haswell server CPU via this OpenBenchmarking.org result file.