AMD Zen 1 Linux Performance Hit From Retbleed, Accumulated CPU Mitigation Impact

Last week I posted my initial benchmarks for the Linux impact of mitigating Retbleed as the newest CPU speculative execution vulnerability. As noted in the prior Retbleed articles, on the AMD side it's Zen 1/1+/2 processors affected as well as older Bulldozer CPUs. That earlier article included Zen 2 benchmarks while in this article are Zen 1 tests given its situation is slightly different.