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From: Nick Piggin <npiggin@suse.de>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	linux-mm@kvack.org,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC V2 SLEB 00/14] The Enhanced(hopefully) Slab Allocator
Date: Fri, 28 May 2010 18:39:06 +1000	[thread overview]
Message-ID: <20100528083906.GB22536@laptop> (raw)
In-Reply-To: <alpine.DEB.2.00.1005271149480.7221@router.home>

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.

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  reply	other threads:[~2010-05-28  8:39 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-21 21:14 [RFC V2 SLEB 00/14] The Enhanced(hopefully) Slab Allocator Christoph Lameter
2010-05-21 21:14 ` [RFC V2 SLEB 01/14] slab: Introduce a constant for a unspecified node Christoph Lameter
2010-06-07 21:44   ` David Rientjes
2010-06-07 22:30     ` Christoph Lameter
2010-06-08  5:41       ` Pekka Enberg
2010-06-08  6:20         ` David Rientjes
2010-06-08  6:34           ` Pekka Enberg
2010-06-08 23:35             ` David Rientjes
2010-06-09  5:55               ` Pekka Enberg
2010-06-09  5:55                 ` Pekka Enberg
2010-06-09  6:20                 ` David Rientjes
2010-06-09  6:20                   ` David Rientjes
2010-05-21 21:14 ` [RFC V2 SLEB 02/14] SLUB: Constants need UL Christoph Lameter
2010-05-21 21:14 ` [RFC V2 SLEB 03/14] SLUB: Use kmem_cache flags to detect if Slab is in debugging mode Christoph Lameter
2010-06-08  3:57   ` David Rientjes
2010-05-21 21:14 ` [RFC V2 SLEB 04/14] SLUB: discard_slab_unlock Christoph Lameter
2010-05-21 21:14 ` [RFC V2 SLEB 05/14] SLUB: is_kmalloc_cache Christoph Lameter
2010-06-08  8:54   ` David Rientjes
2010-05-21 21:14 ` [RFC V2 SLEB 06/14] SLUB: Get rid of the kmalloc_node slab Christoph Lameter
2010-06-09  6:14   ` David Rientjes
2010-06-09 16:14     ` Christoph Lameter
2010-06-09 16:26       ` Pekka Enberg
2010-06-10  6:07         ` Pekka Enberg
2010-05-21 21:14 ` [RFC V2 SLEB 07/14] SLEB: The Enhanced Slab Allocator Christoph Lameter
2010-05-21 21:15 ` [RFC V2 SLEB 08/14] SLEB: Resize cpu queue Christoph Lameter
2010-05-21 21:15 ` [RFC V2 SLEB 09/14] SLED: Get rid of useless function Christoph Lameter
2010-05-21 21:15 ` [RFC V2 SLEB 10/14] SLEB: Remove MAX_OBJS limitation Christoph Lameter
2010-05-21 21:15 ` [RFC V2 SLEB 11/14] SLEB: Add per node cache (with a fixed size for now) Christoph Lameter
2010-05-21 21:15 ` [RFC V2 SLEB 12/14] SLEB: Make the size of the shared cache configurable Christoph Lameter
2010-05-21 21:15 ` [RFC V2 SLEB 13/14] SLEB: Enhanced NUMA support Christoph Lameter
2010-05-21 21:15 ` [RFC V2 SLEB 14/14] SLEB: Allocate off node objects from remote shared caches Christoph Lameter
2010-05-22  8:37 ` [RFC V2 SLEB 00/14] The Enhanced(hopefully) Slab Allocator Pekka Enberg
2010-05-24  7:03 ` Nick Piggin
2010-05-24 15:06   ` Christoph Lameter
2010-05-25  2:06     ` Nick Piggin
2010-05-25  6:55       ` Pekka Enberg
2010-05-25  7:07         ` Nick Piggin
2010-05-25  8:03           ` Pekka Enberg
2010-05-25  8:03             ` Pekka Enberg
2010-05-25  8:16             ` Nick Piggin
2010-05-25  8:16               ` Nick Piggin
2010-05-25  9:19               ` Pekka Enberg
2010-05-25  9:19                 ` Pekka Enberg
2010-05-25  9:34                 ` Nick Piggin
2010-05-25  9:34                   ` Nick Piggin
2010-05-25  9:53                   ` Pekka Enberg
2010-05-25  9:53                     ` Pekka Enberg
2010-05-25 10:19                     ` Nick Piggin
2010-05-25 10:19                       ` Nick Piggin
2010-05-25 10:45                       ` Pekka Enberg
2010-05-25 10:45                         ` Pekka Enberg
2010-05-25 11:06                         ` Nick Piggin
2010-05-25 11:06                           ` Nick Piggin
2010-05-25 15:13                         ` Linus Torvalds
2010-05-25 15:13                           ` Linus Torvalds
2010-05-25 15:43                           ` Nick Piggin
2010-05-25 15:43                             ` Nick Piggin
2010-05-25 17:02                             ` Pekka Enberg
2010-05-25 17:02                               ` Pekka Enberg
2010-05-25 17:19                               ` Nick Piggin
2010-05-25 17:19                                 ` Nick Piggin
2010-05-25 17:35                                 ` Pekka Enberg
2010-05-25 17:35                                   ` Pekka Enberg
2010-05-25 17:40                                   ` Nick Piggin
2010-05-25 17:40                                     ` Nick Piggin
2010-05-25 10:07               ` David Rientjes
2010-05-25 10:07                 ` David Rientjes
2010-05-25 10:02             ` David Rientjes
2010-05-25 10:02               ` David Rientjes
2010-05-25 10:47               ` Pekka Enberg
2010-05-25 10:47                 ` Pekka Enberg
2010-05-25 19:57                 ` David Rientjes
2010-05-25 19:57                   ` David Rientjes
2010-05-25 14:13       ` Christoph Lameter
2010-05-25 14:34         ` Nick Piggin
2010-05-25 14:43           ` Nick Piggin
2010-05-25 14:48           ` Christoph Lameter
2010-05-25 15:11             ` Nick Piggin
2010-05-25 15:28               ` Christoph Lameter
2010-05-25 15:37                 ` Nick Piggin
2010-05-27 14:24                   ` Christoph Lameter
2010-05-27 14:37                     ` Nick Piggin
2010-05-27 15:52                       ` Christoph Lameter
2010-05-27 16:07                         ` Nick Piggin
2010-05-27 16:57                           ` Christoph Lameter
2010-05-28  8:39                             ` Nick Piggin [this message]
2010-05-25 14:40         ` Nick Piggin
2010-05-25 14:48           ` Christoph Lameter
2010-05-25 15:12             ` Nick Piggin

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