Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH 15/15] x86: Fix cpu_coregroup_mask to return correct cpumask on multi-node processors | From | Peter Zijlstra <> | Date | Tue, 25 Aug 2009 12:35:02 +0200 |
| |
On Tue, 2009-08-25 at 12:24 +0200, Andreas Herrmann wrote: > On Tue, Aug 25, 2009 at 11:55:43AM +0200, Peter Zijlstra wrote: > > On Tue, 2009-08-25 at 11:31 +0200, Andreas Herrmann wrote: > > > On Mon, Aug 24, 2009 at 05:36:16PM +0200, Peter Zijlstra wrote: > > > > On Thu, 2009-08-20 at 15:46 +0200, Andreas Herrmann wrote: > > > > > The correct mask that describes core-siblings of an processor > > > > > is topology_core_cpumask. See topology adapation patches, especially > > > > > http://marc.info/?l=linux-kernel&m=124964999608179 > > > > > > > > > > > > argh, violence, murder kill.. this is the worst possible hack and you're > > > > extending it :/ > > > > > > So this is the third code area > > > (besides sched_*_power_savings sysfs interface, and the __cpu_power fiddling) > > > that is crap, mess, a hack. > > > > > > Didn't know that I'd enter such a minefield when touching this code. ;-( > > > > Yeah, you're lucky that way ;-) Its been creaking for a while, and I've > > been making noises to the IBM people (who so far have been the main > > source of power saving patches) to clean this up, but now you trod onto > > all of it at once.. > > > > > What would be your perferred solution for the > > > core_cpumask/llc_shared_map stuff? Another domain level to get rid of > > > this function? > > > > Right, I'd like to see everything exposed as domain levels. > > > > > > numa-cluster > > numa > > socket > > in-socket-numa > > multi-core > > shared-cache > > core > > threads > > > > We currently have a fixed order of these things, but I think we should > > simply provide helpers for building the sd tree and let the arch code do > > that instead of exporting all these masks in a fixed order. > > > > Once we get the arch domain tree, we do degenerate stuff to cull all the > > trivial domains and fold SD flags. > > So any in-socket-numa is only going to haeppen with the arch-defined > domain tree.
Well, we could see what it takes to make this work without that. I mean, this is just how I'd like to see it end up, doesn't mean we cannot work on it from multiple angles at the same time.
> Now that this is settled you should throw away the > __build_sched_domains cleanup patches that are in tip. They won't be > of use when domain creation code is basically changed.
I'm not sure that's needed, we can continue work on refactoring that. Small steps towards something better seems a better plan than a single large step.
| ![\](/images/icornerr.gif) |