From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx148.postini.com [74.125.245.148]) by kanga.kvack.org (Postfix) with SMTP id 456886B0074 for ; Wed, 4 Jul 2012 11:59:58 -0400 (EDT) Received: by ggm4 with SMTP id 4so8157806ggm.14 for ; Wed, 04 Jul 2012 08:59:57 -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: Wed, 4 Jul 2012 18:59:57 +0300 Message-ID: Subject: Re: [PATCH 1/3 v2] slub: prefetch next freelist pointer in __slab_alloc() From: Pekka Enberg Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: JoonSoo Kim Cc: Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Eric Dumazet , David Rientjes 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. -- 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