On Thu, Aug 28, 2014 at 12:46:36PM -0700, Jason Low wrote: > On Wed, 2014-08-27 at 16:32 -0700, Tim Chen wrote:
> > If there are multiple non-forced updates, option 1's error seems to > > accumulate and non-bounded as we do not actually update? > > Is this a concern? > > It should be fine. Once the delta is large enough, we will end up doing > the update anyway. Well, the thing is you can have nr_cpus * 12.5% of outstanding delta; that might be a lot, esp on the large machines. Now there's two problems with all this; the first is the relative threshold, typically such per-cpu things have a fixed update threshold, this makes it much easier to qualify the actual error. Secondly the indeed the nr_cpus in the error bound. Some things; like the proportion code scale the threshold by log2(nr_cpus) in an attempt to do something sensible there. But yes, unbounded errors here are a problem, sure relaxing the updates makes things go fast, they also make things go skew. -- 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/
