On Thu, May 27, 2010 at 11:57:54AM -0500, Christoph Lameter wrote: > On Fri, 28 May 2010, Nick Piggin wrote: > > > > > realized that incremental improvements to SLAB would likely be a > > > > far better idea. > > > > > > It looked to me as if there was a major conceptual issue with the linked > > > lists used for objects that impacted performance > > > > With SLQB's linked list? No. Single threaded cache hot performance was > > the same (+/- a couple of cycles IIRC) as SLUB on your microbenchmark. > > On Intel's OLTP workload it was as good as SLAB. > > > > The linked lists were similar to SLOB/SLUB IIRC. > > Yes that is the problem. So it did not address the cache cold > regressions in SLUB. SLQB mostly addressed the slow path frequency on > free. This is going a bit off topic considering that I'm not pushing SLQB or any concept from SLQB (just yet at least). As far as I know there were no cache cold regressions in SLQB. > The design of SLAB is superior for cache cold objects since SLAB does > not touch the objects on alloc and free (if one requires similar > cache cold performance from other slab allocators) thats why I cleaned > up the per cpu queueing concept in SLAB (easy now with the percpu > allocator and operations) and came up with SLEB. At the same time this > also addresses the slowpath issues on free. I am not entirely sure how to > deal with the NUMAness but I want to focus more on machines with low node > counts. > > The problem with SLAB was that so far the "incremental improvements" have > lead to more deteriorations in the maintainability of the code. There are > multiple people who have tried going this route that you propose. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>