That is also what I immediately noticed. The graphs showed that the slow runs were around ~4s (p50) or ~7s (p90), and then also mention that Linux was 5-10x fa

That is also what I immediately noticed. The graphs showed that the slow runs were around ~4s (p50) or ~7s (p90), and then also mention that Linux was 5-10x faster. This would mean the same operations on Linux are somewhere around 1s in the worst case, which is perhaps even faster than their sped up system. But instead they had to build all this extra junk like an additional caching layer and daemon (wasting memory and CPU) atop the kernel's existing cache just to work around the kernel being slow.