On Tue, Jan 07, 2014 at 02:32:07PM +0100, Vincent Guittot wrote: > On 7 January 2014 14:15, Peter Zijlstra <pet...@infradead.org> wrote: > > On Tue, Jan 07, 2014 at 01:59:30PM +0100, Peter Zijlstra wrote: > >> On Tue, Jan 07, 2014 at 12:55:18PM +0000, Morten Rasmussen wrote: > >> > My understanding is that should_we_balance() decides which cpu is > >> > eligible for doing the load balancing for a given domain (and the > >> > domains above). That is, only one cpu in a group is allowed to load > >> > balance between the local group and other groups. That cpu would > >> > therefore be reponsible for pulling enough load that the groups are > >> > balanced even if it means temporarily overloading itself. The other cpus > >> > in the group will take care of load balancing the extra load within the > >> > local group later. > >> > >> Correct. > > > > On that; one of the things I wanted to (and previously did attempt but > > failed) is trying to rotate this cpu. Currently its always the first cpu > > (of the group) and that gives a noticeable bias. > > Isn't the current policy (it's the 1st idle cpu in priority). a good > enough way to rotate the cpus ? Are you need the rotation for loaded > use case too ?
Yeah its for the fully loaded case. And like I said, there's not been many complaints on this. The 'problem' is that its always same cpu that does the most expensive full machine balance; and always that cpu that is the one that gains extra load to redistribute in the group. So its penalized twice. Like said, really minor issue. Just something I thought I'd mention. -- 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/
