Messages in this thread | | | Date | Wed, 15 Jul 2009 16:59:07 +0200 | From | Nick Piggin <> | Subject | Re: [RFC][PATCH] Check write to slab memory which freed already using mudflap |
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On Fri, Jul 10, 2009 at 03:03:19AM -0700, David Rientjes wrote: > On Fri, 10 Jul 2009, Pekka Enberg wrote: > > > Hey, I said SLAB is on its way out (yes, it really is). But I didn't say > > we're going to blindly remove it if performs better than the > > alternatives. I don't see any reason why SQLB can't reach the same > > performance as SLAB after on fundamental level, though. Can you? > > > > I'm not really interested in making predictions on which design has the > greatest potential for pure performance, I'm interested in what is proven > to work and does the job better than any alternative. Right now, for > certain workloads, that's undeniably slab. So I'd disagree that slab is > on its way out until another allocator is shown to at least have parity > with it (at which time I'd become more interested in the cleanliness of > the code, the debugging support, etc.). > > It's my opinion that slab is on its way out when there's no benchmark that > shows it is superior by any significant amount. If that happens (and if > its successor is slub, slqb, or a yet to be implemented allocator), we can > probably start a discussion on what's in and what's out at that time.
How are you running your netperf test? Over localhost or remotely? It is a 16 core system? NUMA?
It seems pretty variable when I run it here, although there seems to be a pretty clear upper bound on performance, where a lot of the results land around (then others go anywhere down to less than half that performance).
Anyway, tried to get an idea of performance on my 8 core NUMA system, over localhost, and just at 64 threads. Ran the test 60 times for each allocator.
Rates for 2.6.31-rc2 (+slqb from Pekka's tree) SLAB: 1869710 SLQB: 1859710 SLUB: 1769400
Slab did have slightly higher maximal numbers too, although slqb SLQB had the highest minimum. But both were fairly similar there. SLUB's minimum went down to around 13% lower than the others.
Now I didn't reboot or restart netperf server during runs, so there is possibility of results drifting for some reason (eg. due to cache/node placment).
I can't say SLQB beats SLAB here, but it's fairly good. I'll see if any tweaks can improve it further...
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