Re: Active waiting with yield()

[Mikulas Patocka]

On Sat, 15 Nov 2008, Peter Zijlstra wrote:

> On Fri, 2008-11-14 at 16:41 -0500, Mikulas Patocka wrote:
> 
> > So, use msleep(1) instead of yield() ?
> 
> wait_event() of course!

Why? Why developes don't like active waiting when terminating a driver?
Is there any real workload when 1ms delay on driver unload would be 
problematic? Or don't they like it because of coding style?

L1 cache miss --- 10ns --- on every request, when using wait queues
msleep latency --- 1ms --- on driver termination, when using msleep
--- so if the driver processes more than 100000 requests between reboots, 
wait queues actually slow things down.

Mikulas
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