SLUB with queueing (V2) beats SLAB netperf TCP_RR
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From: Christoph Lameter on 13 Jul 2010 22:10 On Tue, 13 Jul 2010, Heinz Diehl wrote: > On 13.07.2010, Christoph Lameter wrote: > > > Can you get us the config file. What is the value of > > PERCPU_DYMAMIC_EARLY_SIZE? > > My .config file is attached. I don't know how to find out what value > PERCPU_DYNAMIC_EARLY_SIZE is actually on, how could I do that? There's > no such thing in my .config. I dont see anything in there at first glance that would cause slub to increase its percpu usage. This is straight upstream? Try to just comment out the BUILD_BUG_ON. I had it misfire before and fixed the formulae to no longer give false positives. Maybe that is another case. Tejun wanted that but never was able to give me an exact formular to check for. At the Ottawa Linux Symposium right now so responses may be delayed. Hotels Internet connection keeps getting clogged for some reason. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Tejun Heo on 14 Jul 2010 07:50 Hello, On 07/12/2010 05:11 PM, Christoph Lameter wrote: > You need a sufficient PERCPU_DYNAMIC_EARLY_SIZE to be configured. What > platform is this? Tejon: You suggested the BUILD_BUG_ON(). How can he > increase the early size? The size is determined by PERCPU_DYNAMIC_EARLY_SIZE, so bumping it up should do it but it would probably be wiser to bump PERCPU_DYNAMIC_RESERVE too. PERCPU_DYNAMIC_EARLY_SIZE is currently 12k. How high should it be? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Tejun Heo on 14 Jul 2010 08:00 Hello, On 07/14/2010 04:01 AM, Christoph Lameter wrote: > I dont see anything in there at first glance that would cause slub to > increase its percpu usage. This is straight upstream? It's basically checking constant expressions there and PERCPU_DYNAMIC_EARLY_SIZE is defined as 12k, so slub is thinking that it's gonna use more memory on that build. > Try to just comment out the BUILD_BUG_ON. I had it misfire before and > fixed the formulae to no longer give false positives. Maybe that is > another case. Tejun wanted that but never was able to give me an exact > formular to check for. Yeah, unfortunately, due to alignment requirements, it can't be determined with accuracy. We'll just have to size it sufficiently. > At the Ottawa Linux Symposium right now so responses may be delayed. > Hotels Internet connection keeps getting clogged for some reason. I'm in suse labs conf until next week so I don't think I'll be doing much till then either. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Heinz Diehl on 14 Jul 2010 10:30 On 14.07.2010, Christoph Lameter wrote: > I dont see anything in there at first glance that would cause slub to > increase its percpu usage. This is straight upstream? Yes ,it's plain vanilla 2.6.35-rc4/-rc5 from kernel.org. > Try to just comment out the BUILD_BUG_ON. I first bumped it up to 24k, but that was obviously not enough, so I commented out the BUILD_BUG_ON which triggers the build error. Now It builds fine, and I'll do some testing. Thanks, Heinz. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: David Rientjes on 14 Jul 2010 16:30
On Tue, 13 Jul 2010, Christoph Lameter wrote: > > > Can you get us the config file. What is the value of > > > PERCPU_DYMAMIC_EARLY_SIZE? > > > > My .config file is attached. I don't know how to find out what value > > PERCPU_DYNAMIC_EARLY_SIZE is actually on, how could I do that? There's > > no such thing in my .config. > > I dont see anything in there at first glance that would cause slub to > increase its percpu usage. This is straight upstream? > The problem is that he has CONFIG_NODES_SHIFT=10 and struct kmem_cache has an array of struct kmem_cache_node pointers with MAX_NUMNODES entries which blows its size up to over 8K. That's probably overkill for his quad-core 8GB AMD, so I'd recommend lowering CONFIG_NODES_SHIFT to 6. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |