From: Eric Dumazet <[EMAIL PROTECTED]>
Date: Thu, 15 Nov 2007 09:25:59 +0100
> Please note that :
>
> if (need_resched())
> cond_resched();
>
> will re-test need_resched() once cond_resched() is called.
>
> So it may sound unnecessary but in the rt_check_expire() case, with a loop
> potentially doing XXX.XXX iterations, being able to bypass the function call
> is a clear win (in my bench case, 25 ms instead of 88 ms). Impact on I-cache
> is irrelevant here as this rt_check_expires() runs once every 60 sec.
BTW, Eric, initially I was going to recommend that you do
something like:
if ((goal % SOME_POWER_OF_2) == 0)
cond_resched();
to mitigate this cost but decided it wasn't worth the bother.
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