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The trend of multicore and NUMA means that hardware increasingly looks like a traditional network of many separate computers. The natural conclusions of single-
by vacuity 1y ago
The trend of multicore and NUMA means that hardware increasingly looks like a traditional network of many separate computers. The natural conclusions of single-core scaled up to, say, 4 cores, shift when there are 8+ cores. Locality becomes crucial; just as you wouldn't split up data-path dependencies across LANs, you shouldn't split them up across NUMA sockets either. Ignoring arguments about locking, message passing, cache management, and whatever, the most pressing argument for multikernels (or at least, far increased per-core state and reduced shared state) is that locality is essential for performance.
- layla5alive 1y agoYup, data movement and contention and coherencey are the things that will increasingly dominate power use as core scaling continues. Exploiting locality is a must for high performance systems. Linux would benefit from a scheduler per CCD (in AMD parlance) approach being a first-class option. CCD pinning is a mechanism to push in this direction today, but partitioning kernel scheduler(s) along hardware boundaries would reduce complexity and overhead for a lot of use cases..