On Mon, Sep 24, 2012 at 1:39 PM, Benjamin Segall <bseg...@google.com> wrote: > blocked_load_avg ~= \sum_child > child.runnable_avg_sum/child.runnable_avg_period * child.weight > > The thought was: So if all the children have hit zero runnable_avg_sum > (or in the case of a child task, will when they wake up), then > blocked_avg sum should also hit zero at the same and we're in theory > fine. > > However, child load can be significantly larger than even the maximum > value of runnable_avg_sum (and you can get a full contribution off a new > task with only one tick of runnable_avg_sum anyway...), so > runnable_avg_sum can hit zero first due to rounding. We should case on > runnable_avg_sum || blocked_load_avg.
Clipping blocked_load_avg when runnable_avg_sum goes to zero is sufficient. At this point we cannot contribute to our parent anyway. > > > As a side note, currently decay_load uses SRR, which means none of these > will hit zero anyway if updates occur more often than once per 32ms. I'm > not sure how we missed /that/, but fixes incoming. Egads, fixed. We definitely used to have that, I think it got lost in the "clean everything up, break it into a series, and make it pretty" step. Perhaps that explains why some of the numbers in the previous table were a little different. > > Thanks, > Ben > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/