Messages in this thread | | | Date | Fri, 08 Oct 2004 16:08:08 +1000 | From | Nick Piggin <> | Subject | Re: [Lse-tech] Re: [RFC PATCH] scheduler: Dynamic sched_domains |
| |
Takayoshi Kochi wrote:
> Yup, if SD_NODES_PER_DOMAIN is set to 4, our 32-way TX-7 have > two disjoint domains ;( > (though the current default is 6 for ia64...) > > I think the default configuration of the scheduler domains should be > as identical to its real hardware topology as possible, and should > modify the default only when necessary (e.g. for Altix). >
That is the idea. Unfortunately the ia64 modifications are ia64 wide. I don't think it should be too hard to make it sn2 only.
> Right now with the sched domain scheduler, we have to setup the > domain hierarcy only at boot time statically, which makes it harder to > find the optimal domain topology/parameter. The dynamic patch > makes it easier to modify the default configuration. >
No you don't have to. If you have a look at the work in -mm, basically the whole thing gets recreated on every hoplug operation. It would be trivial to modify some parameters then reinit the domains in the same way.
N disjoint domains can be trivially handled by making N passes over the init code, each using a different set of CPUs as its "cpu_possible_map". This can easily be done dynamically by using the above method.
> If the scheduler gains more dynamic configurability like what Jesse > said, it adds more flexibility for runtime optimization and seems > a way to go. I'm not sure runtime configurability of domain topology > is necessary for all users, but it's extremely useful for developers. >
That would be nice. The patch queue is pretty well clogged up at the moment, so I'm not going to look at the scheduler again until all the patches from -mm get into 2.6.10-bk. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |