Re: [PATCH 3/5] Use next_balance instead of last_balance

[Nick Piggin]

Nick Piggin wrote:
> Christoph Lameter wrote:
>
> > Use next_balance instead of last_balance ...
> >
> > The cpu offset calculation in the sched_domains code makes it 
> > difficult to
> > figure out when the next event is supposed to happen since we only keep
> > track of the last_balancing. We want to know when the next load balance
> > is supposed to occur.
> >
> > Move the cpu offset calculation into build_sched_domains(). Do the
> > setup of the staggered load balance schewduling when the sched domains
> > are initialized. That way we dont have to worry about it anymore later.
> >
> > This also in turn simplifies the load balancing time checks.
>
>
> OK. I think I made this overcomplex in order to cope with issues where
> offset can get skewed so if we're unlucky they might all get into synch
> ... but this new code isn't any worse than the old, and it is cheaper.
>
> So, Ack.

Actually, it is wrong, so nack.

You didn't take into account that balance_interval may have changed,
and so might the idle status.

--
SUSE Labs, Novell Inc.
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