Messages in this thread |  | | | Date | Wed, 07 Dec 2005 10:08:41 +1100 | | From | Nick Piggin <> | | Subject | Re: [RFC 1/3] Framework for accurate node based statistics |
| |
Christoph Lameter wrote: > [RFC] Framework for accurate node based statistics > > Currently we have various vm counters that are split per cpu. This arrangement > does not allow access to per node statistics that are important to optimize > VM behavior for NUMA architectures. All one can say from the per_cpu > differential variables is how much a certain variable was changed by this cpu > without being able to deduce how many pages in each node are of a certain type. > > This patch introduces a generic framework to allow accurate per node vm > statistics through a large per node and per cpu array. The numbers are > consolidated when the slab drainer runs (every 3 seconds or so) into global > and per node counters. VM functions can then check these statistics by > simply accessing the node specific or global counter. > > A significant problem with this approach is that the statistics are only > accumulated every 3 seconds or so. I have tried various other approaches > but they typically end up with having to add atomic variables to critical > VM paths. I'd be glad if someone else had a bright idea on how to improve > the situation. >
Why not have per-node * per-cpu counters?
Or even use the current per-zone * per-cpu counters, and work out your node details from there?
-- SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
- 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/
|  |