Messages in this thread | | | Date | Sat, 3 Nov 2007 12:33:01 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [PATCH 2/2] slub: fix Objects count |
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On Sat, 3 Nov 2007, Hugh Dickins wrote:
> I was afraid you might say something like that. > Perhaps it'll be a patch I need to use in my own builds. > Though I'd have thought others would want that accuracy too. > Didn't SLAB give it? (The "r*gr*ss**n" word!)
Slab also only counts objects that are not in the queues. See free_block() f.e.
We could improve the situation by flushing all cpu slabs before counts are determined.
Which can be done manually. Run
slabinfo -s
and then look at the numbers.
> > Adds to much overhead to the fast paths > > You've come to that conclusion very quickly!
I have just spend a few weeks optimizing the fast and slow paths and there is some additional overhead that I am still trying to eliminate.
> Any numbers to back it up?
The performance in the fast paths depends on updating only a single word for an allocation. Adding another counter makes that impossible.
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