From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id D5F276B0078 for ; Wed, 4 Jul 2012 12:04:17 -0400 (EDT) Received: by obhx4 with SMTP id x4so9346516obh.14 for ; Wed, 04 Jul 2012 09:04:17 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1340389359-2407-1-git-send-email-js1304@gmail.com> <1340390729-2821-1-git-send-email-js1304@gmail.com> Date: Thu, 5 Jul 2012 01:04:16 +0900 Message-ID: Subject: Re: [PATCH 1/3 v2] slub: prefetch next freelist pointer in __slab_alloc() From: JoonSoo Kim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Eric Dumazet , David Rientjes 2012/7/5 Pekka Enberg : > On Wed, Jul 4, 2012 at 6:45 PM, JoonSoo Kim wrote: >>> Prefetching can also have negative effect on overall performance: >>> >>> http://lwn.net/Articles/444336/ >> >> Thanks for good article which is very helpful to me. >> >>> That doesn't seem like that obvious win to me... Eric, Christoph? >> >> Could you tell me how I test this patch more deeply, plz? >> I am a kernel newbie and in the process of learning. >> I doesn't know what I can do more for this. >> I googling previous patch related to slub, some people use netperf. >> >> Just do below is sufficient? >> How is this test related to slub? >> >> for in in `seq 1 32` >> do >> netperf -H 192.168.0.8 -v 0 -l -100000 -t TCP_RR > /dev/null & >> done >> wait > > The networking subsystem is sensitive to slab allocator performance > which makes netperf an interesting benchmark, that's all. > > As for slab benchmarking, you might want to look at what Mel Gorman > has done in the past: > > https://lkml.org/lkml/2009/2/16/252 > > For something like prefetch optimization, you'd really want to see a > noticeable win in some benchmark. The kind of improvement you're > seeing with your patch is likely to be lost in the noise - or even > worse, cause negative performance for real world workloads. Okay. Thanks for comments. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org