This feature is pretty niche and really only helps on high thread count workloads (relative to the number of cores). Otherwise you can use per-thread data and i

This feature is pretty niche and really only helps on high thread count workloads (relative to the number of cores). Otherwise you can use per-thread data and it'll be the same, since the number of threads is approximately (or less than) the number of cores. What workloads are high thread count? Mainly servers, I think (at least I don't know if any others offhand). So OSes aimed for embedded use or desktop use don't gain much from this sort of thing. Linux dominates the server market.