From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx134.postini.com [74.125.245.134]) by kanga.kvack.org (Postfix) with SMTP id B8B866B0032 for ; Wed, 10 Jul 2013 21:05:09 -0400 (EDT) Date: Thu, 11 Jul 2013 10:05:10 +0900 From: Joonsoo Kim Subject: Re: [RFC PATCH 0/5] Support multiple pages allocation Message-ID: <20130711010510.GC7756@lge.com> References: <1372840460-5571-1-git-send-email-iamjoonsoo.kim@lge.com> <20130703152824.GB30267@dhcp22.suse.cz> <51D44890.4080003@gmail.com> <51D44AE7.1090701@gmail.com> <20130704042450.GA7132@lge.com> <20130704100044.GB7833@dhcp22.suse.cz> <20130710003142.GA2152@lge.com> <20130710091703.GD4437@dhcp22.suse.cz> <20130710095533.GA5557@lge.com> <20130710112737.GG4437@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130710112737.GG4437@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Zhang Yanfei , Andrew Morton , Mel Gorman , David Rientjes , Glauber Costa , Johannes Weiner , KOSAKI Motohiro , Rik van Riel , Hugh Dickins , Minchan Kim , Jiang Liu , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, Jul 10, 2013 at 01:27:37PM +0200, Michal Hocko wrote: > On Wed 10-07-13 18:55:33, Joonsoo Kim wrote: > > On Wed, Jul 10, 2013 at 11:17:03AM +0200, Michal Hocko wrote: > > > On Wed 10-07-13 09:31:42, Joonsoo Kim wrote: > > > > On Thu, Jul 04, 2013 at 12:00:44PM +0200, Michal Hocko wrote: > [...] > > > > > Which benchmark you are using for this testing? > > > > > > > > I use my own module which do allocation repeatedly. > > > > > > I am not sure this microbenchmark will tell us much. Allocations are > > > usually not short lived so the longer time might get amortized. > > > If you want to use the multi page allocation for read ahead then try to > > > model your numbers on read-ahead workloads. > > > > Of couse. In later, I will get the result on read-ahead workloads or > > vmalloc workload which is recommended by Zhang. > > > > I think, without this microbenchmark, we cannot know this modification's > > performance effect to single page allocation accurately. Because the impact > > to single page allocation is relatively small and it is easily hidden by > > other factors. > > The main thing is whether the numbers you get from an artificial > microbenchmark matter at all. You might see a regression which cannot be > hit in practice because other effects are of magnitude more significant. Okay. I will keep this in mind. Thanks for your comment. > -- > Michal Hocko > SUSE Labs > > -- > 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 -- 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