Hello, On Thu, Dec 06, 2012 at 01:08:18PM -0500, Jeff Moyer wrote: > > As for the original patch, I think it's a bit too much to expose to > > userland. It's probably a good idea to bind the flusher to the local > > node but do we really need to expose an interface to let userland > > control the affinity directly? Do we actually have a use case at > > hand? > > Yeah, folks pinning realtime processes to a particular cpu don't want > the flusher threads interfering with their latency. I don't have any > performance numbers on hand to convince you of the benefit, though.
What I don't get is, RT tasks win over bdi flushers every time and I'm skeptical allowing bdi or not on a particular CPU would make a big difference on non-RT kernels anyway. If the use case calls for stricter isolation, there's isolcpus. While I can see why someone might think that they need something like this, I'm not sure it's actually something necessary. And, even if it's actually something necessary, I think we'll probably be better off with adding a mechanism to notify userland of new kthreads and let userland adjust affinity using the usual mechanism rather than adding dedicated knobs for each kthread users. Thanks. -- tejun -- 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/
