On Mon, Jul 28, 2014 at 07:19:09PM +0200, Peter Zijlstra wrote: > > > And here we try and make good on that assumption. The thing I worry > > > about is what happens if the machine is entirely idle... > > > > > > What guarantees an semi up-to-date cfs_rq->avg.last_update_time. > > > > update_blocked_averages I think should do just as good a job as the old > > code, which isn't perfect but is about as good as you can get worst case. > > Right, that's called from rebalance_domains() which should more or less > update this value on tick boundaries or thereabouts for most 'active' > cpus. > > But if the entire machine is idle, the first wakeup (if its a x-cpu one) > might see a very stale timestamp. > > If we can fix that, that would be good I suppose, but I'm not > immediately seeing something pretty there, but you're right, it'd not be > worse than the current situation.
It matters time is up-to-date before load_avg is actually used. So yes, we should have already achieved that. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
