On Tue, Jul 21, 2015 at 09:08:07AM +0800, Boqun Feng wrote: > Hi Yuyang, > > On Wed, Jul 15, 2015 at 08:04:41AM +0800, Yuyang Du wrote: > > The cfs_rq's load_avg is composed of runnable_load_avg and blocked_load_avg. > > Before this series, sometimes the runnable_load_avg is used, and sometimes > > the load_avg is used. Completely replacing all uses of runnable_load_avg > > with load_avg may be too big a leap, i.e., the blocked_load_avg is concerned > > to result in overrated load. Therefore, we get runnable_load_avg back. > > > > The new cfs_rq's runnable_load_avg is improved to be updated with all of the > > runnable sched_eneities at the same time, so the one sched_entity updated > > and > > the others stale problem is solved. > > > > How about tracking cfs_rq's blocked_load_avg instead of > runnable_load_avg, because, AFAICS: > > cfs_rq->runnable_load_avg = se->avg.load_avg - cfs_rq->blocked_load_avg.
No, cfs_rq->runnable_load_avg = cfs_rq->avg.load_avg - cfs_rq->blocked_load_avg, without rounding errors and the like. > se is the corresponding sched_entity of cfs_rq. And when we need the > runnable_load_avg, we just calculate by the expression above. > > This can be thought as a lazy way to update runnable_load_avg, and we > don't need to modify __update_load_avg any more. Not lazy at all, but adding (as of now) useless blocked_load_avg and an extra subtraction. Or did you forget blocked_load_avg also needs to be updated/decayed as time elapses? -- 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/
