Re: [PATCH] sched: remove sched_find_first_bit()

[Ingo Molnar]

* Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx> wrote:

> sched_find_first_bit() is in fact the unrolled version of
> find_first_bit(), which is theoretically faster in some cases.
> But in the kernel it is called only in couple places in 
> kernel/sched/rt.c, and both of them are not looking like hot
> paths [...]

They are in terms of scheduling: pick_next_rt_entity() is in the RT scheduling 
fastpath.

Which makes me just suspicious of how careful this patch really is:

> that will doubtly achieve measurable benefit from using unrolled version of 
> find_first_bit() - there's no hard loops, and the execution path is not really 
> short.

... that's really just handwaving. Numbers please.

Thanks,

	Ingo