The Performance Impact Of MDS / Zombieload Plus The Overall Cost Now Of Spectre/Meltdown/L1TF/MDS

The code compilation speed on the AMD systems were roughly the same with its default mitigations while the Intel systems with all of their default mitigations were a few seconds slower or much slower obviously when disabling Hyper Threading.

The Core i7 class CPUs for mostly user-space workloads not impaired by the default mitigations did obviously see a performance hit with SMT/HT disabled though less so with the Core i9 given its already high core counts and most of these real-world multi-threaded workloads not scaling anything close to linearly to dozens of threads.

With the Hackbench Linux kernel scheduler benchmark, the default mitigations led to taking almost twice the amount of time as the unmitigated kernel and obviously another hit as well with HT disabled. The AMD systems didn't see any performance impact with their Spectre mitigations.

The Intel systems saw a measurable hit from the CPU mitigations in the glibc micro-benchmarks.