On Fri, Jul 11, 2014 at 01:10:41PM -0500, Christoph Lameter wrote: > On Tue, 8 Jul 2014, Frederic Weisbecker wrote: > > > > I was figuring that a fair number of the kthreads might eventually > > > be using this, not just for the grace-period kthreads. > > > > Ok makes sense. But can we just rename the cpumask to housekeeping_mask? > > That would imply that all no-nohz processors are housekeeping? So all > processors with a tick are housekeeping?
Well, now that I think about it again, I would really like to keep housekeeping to CPU 0 when nohz_full= is passed. > > Could we make that set configurable? Ideally I'd like to have the ability > restrict the housekeeping to one processor. Ah, I'm curious about your usecase. But I think we can do that. And we should. In fact I think that Paul could keep affining grace period kthread to CPU 0 for the sole case when we have nohz_full= parameter passed. I think the performance issues reported to him refer to CONFIG_NO_HZ_FULL=y config without nohz_full= parameter passed. That's the most important to address. Optimizing the "nohz_full= passed" case is probably not very useful and worse it complicate things a lot. What do you think Paul? Can we simplify things that way? I'm pretty sure that nobody cares about optimizing the nohz_full= case. That would really simplify things to stick to CPU 0. -- 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/
