Re: [PATCH 5/7] KVM-GST: KVM Steal time accounting

Peter Zijlstra
2011-06-15T09:28:49Z

On Tue, 2011-06-14 at 22:08 -0300, Glauber Costa wrote:
> >> + while (steal> TICK_NSEC) {
> >
> > /* really, if we wanted a division we'd have
> written one */
> > asm("" : "+rm" (steal));
>
> Out of curiosity, have we seen any compiler de-optimize it to a
> division, or are you just being careful ?
>
> >> + steal -= TICK_NSEC;
> >> + st++;
> >> + }

No that really happened a number of times, there's one in
sched_avg_period() that actually triggered and __iter_div_u64_rem() that
started it all iirc.