Re: [PATCH 2/2] tty: Use unbound workqueue for all input workers

From: Greg Kroah-Hartman
Date: Sun Oct 18 2015 - 00:32:23 EST


On Sat, Oct 17, 2015 at 04:36:24PM -0400, Peter Hurley wrote:
> The commonly accepted wisdom that scheduling work on the same cpu
> that handled interrupt i/o benefits from cache-locality is only
> true if the cpu is idle (since bound kworkers are often the highest
> vruntime and thus the lowest priority).
>
> Measurements of scheduling via the unbound queue show lowered
> worst-case latency responses of up to 5x over bound workqueue, without
> increase in average latency or throughput.
>
> pty i/o test measurements show >3x (!) reduced total running time; tests
> previously taking ~8s now complete in <2.5s.

Wow, nice job with this, that's unexpected.

greg k-h
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