Re: [REPORT] cfs-v4 vs sd-0.44

[Ingo Molnar]

* Rogan Dawes <lists@xxxxxxxxxxxx> wrote:

> >        if (p_to && p->wait_runtime > 0) {
> >                p->wait_runtime >>= 1;
> >                p_to->wait_runtime += p->wait_runtime;
> >        }
> >
> >the above is the basic expression of: "charge a positive bank balance". 
> >
> 
> [..]
> 
> > [note, due to the nanoseconds unit there's no rounding loss to worry 
> > about.]
> 
> Surely if you divide 5 nanoseconds by 2, you'll get a rounding loss?

yes. But not that we'll only truly have to worry about that when we'll 
have context-switching performance in that range - currently it's at 
least 2-3 orders of magnitude above that. Microseconds seemed to me to 
be too coarse already, that's why i picked nanoseconds and 64-bit 
arithmetics for CFS.

	Ingo
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