OS Scheduling with Nest: Keeping Tasks Close Together on Warm Cores
summary
A scheduler patch called Nest keeps a small primary nest of recently used cores plus a reserve nest and briefly does idle spinning to keep cores at higher DVFS levels. Implementation modifies CFS wakeup/select paths and runs on real machines and the Phoronix suite; an LLVM config run gains ~16% and about 40 of 200 Phoronix tests improve while 159 show no change. Results depend on kernel HW P‑state handling so benefits vanish on newer kernels like Linux 5.15.
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chapters (5)
- 0:00Introduction and motivation
- 5:44Nest scheduler core ideas
- 12:58Primary and reserve nests
- 29:23Evaluation and performance results
- 39:45Conclusion and future work
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