A very subjective opinion. CPU performance depends on many factors. The article does not give the results of `perf` performance tests. There are no given kernel parameters either at compile time or set late `sysctl` parameters. How is the RAM allocated to the CPU cores? How are IRQs used? Does RAM have support for error correction? The only fact the article claims is that by setting the `mitigations=off` flag in the system configuration there is some misbalance which can make certain tasks execute slower under certain conditions.<p>Pardon my English, it's not my native language.
If I would guess, for this past 3 years, CPU and software are tested and optimized on a kernel with Spectre-like mitigation-enabled. That caused a lot of trend shifts like don't relies on automatic branch prediction, some code even explicitly avoid the speculative execution altogether, resulting no performance gain on mitigation-disabled. Even more, since they don't test on mitigation-disabled, they failed to noticed the performance issues under mitigation-disabled.