> I think turning the BKL into a semaphore was fine per se,
Are there really that many long lived BKL holders? I have some doubts.
Semaphore makes only sense when the critical region is at least
many thousands of cycles to amortize the scheduling overhead.
Ok perhaps this needs some numbers to decide.
but that was
The semaphores should be still nearly as fast in theory, especially
for the contended case.
Or figure out what made the semaphore consolidation slower? As Ingo
pointed out earlier 40% is unlikely to be a fast path problem, but some
algorithmic problem. Surely that is fixable (even for .26)?
Perhaps we were lucky it showed so easily, not in something tricky.
-Andi
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