RE: [RFC PATCH 1/1] sched: Extend cpu idle state for 1ms

From: David Laight
Date: Fri Aug 04 2023 - 10:04:36 EST

From: Shrikanth Hegde
> Sent: 26 July 2023 09:05
> > + if (sched_clock() < READ_ONCE(rq->idle_end_time) + IDLE_CPU_DELAY_NS)
> Wouldn't this hurt the latency badly? Specially on a loaded system with
> a workload that does a lot of wakeup.

Having spotted this I'm also rather worried about systems
that are doing (eg) real time audio and need to wakeup a
lot of threads (less than the number of cpu) every (say) 10ms.

It is hard enough waking up a lot of threads quickly without
another 1ms delay being added.
(I'm only talking about 30 threads as well, not 300.)


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