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| author | Christian Loehle <christian.loehle@arm.com> | 2026-09-17 16:39:15 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-09-25 12:45:58 +0200 |
| commit | c9ce69fc43bd07dbed9d23a504e56f84604ecf42 (patch) | |
| tree | 52e70501a6805608547805ffca4017d8ba878d4f /tools/lib/python | |
| parent | abe440b3770fce8eb8ee92a563dfb55a7b9a1c0e (diff) | |
sched/fair: Randomize equally shallow slow-path candidates
Picking the first eligible idle CPU leaves a scan-order bias. Concurrent
slow-path selectors can choose the same CPU before either task is enqueued.
Use reservoir sampling for equal exit latencies, resetting the candidate
count when a shallower candidate appears. Use the per-CPU scheduler PRNG
and reciprocal_scale() to avoid variable division or a second scan.
Use a u64 latency key with U64_MAX for unpublished states. Published
states take precedence; when none are found, sample among the idle CPUs
without a published state.
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://patch.msgid.link/20260917153915.1563875-3-christian.loehle@arm.com
Diffstat (limited to 'tools/lib/python')
0 files changed, 0 insertions, 0 deletions