On Mon, Jan 06, 2014 at 04:28:13PM +0000, Peter Zijlstra wrote: > On Mon, Dec 23, 2013 at 06:22:17PM +0100, Dietmar Eggemann wrote: > > I'm not sure if the idea to create a dedicated sched_domain level for every > > topology flag representing a specific functionality will scale. From the > > perspective of energy-aware scheduling we need e.g. energy costs (P and C > > state) which can only be populated towards the scheduler via an additional > > sub-struct and additional function arch_sd_energy() like depicted in > > Morten's email: > > > > [2] lkml.org/lkml/2013/11/14/102 > > That lkml.org link is actually not working for me (blank page -- maybe > lkml.org is on the blink again). > > That said, I yet have to sit down and think about the P state stuff, but > I was thinking we need some rudimentary domain support for that. > > For instance, the big-little thingies seem share their P state per > cluster, so we need a domain at that level to hang some state off of -- > which we actually have in this case. But we need to ensure we do have > it -- somehow.
Is there any examples of frequency domains not matching the span of a sched_domain? I would have thought that we would have a matching sched_domain to hang the P and C state information from for most systems. If not, we could just add it. I don't think it is safe to assume that big-little always has cluster P-states. It is implementation dependent. But the most obvious alternative would be to have per-cpu P-states in which case we would also have a matching sched_domain. -- 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/
