Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757279AbYASKpt (ORCPT ); Sat, 19 Jan 2008 05:45:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753234AbYASKpl (ORCPT ); Sat, 19 Jan 2008 05:45:41 -0500 Received: from fxip-0047f.externet.hu ([88.209.222.127]:60672 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753142AbYASKpk (ORCPT ); Sat, 19 Jan 2008 05:45:40 -0500 To: salikhmetov@gmail.com CC: miklos@szeredi.hu, linux-mm@kvack.org, jakob@unthought.net, linux-kernel@vger.kernel.org, valdis.kletnieks@vt.edu, riel@redhat.com, ksm@42.dk, staubach@redhat.com, jesper.juhl@gmail.com, torvalds@linux-foundation.org, a.p.zijlstra@chello.nl, akpm@linux-foundation.org, protasnb@gmail.com, r.e.wolff@bitwizard.nl, hidave.darkstar@gmail.com, hch@infradead.org In-reply-to: <4df4ef0c0801181148y8d446c7ifb23677dbf4ea0c9@mail.gmail.com> (salikhmetov@gmail.com) Subject: Re: [PATCH -v6 0/2] Fixing the issue with memory-mapped file times References: <12006091182260-git-send-email-salikhmetov@gmail.com> <4df4ef0c0801181148y8d446c7ifb23677dbf4ea0c9@mail.gmail.com> Message-Id: From: Miklos Szeredi Date: Sat, 19 Jan 2008 11:45:35 +0100 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2482 Lines: 61 > 2008/1/18, Miklos Szeredi : > > > 4. Performance test was done using the program available from the > > > following link: > > > > > > http://bugzilla.kernel.org/attachment.cgi?id=14493 > > > > > > Result: the impact of the changes was negligible for files of a few > > > hundred megabytes. > > > > Could you also test with ext4 and post some numbers? Afaik, ext4 uses > > nanosecond timestamps, so the time updating code would be exercised > > more during the page faults. > > > > What about performance impact on msync(MS_ASYNC)? Could you please do > > some measurment of that as well? > > Did a quick test on an ext4 partition. This is how it looks like: Thanks for running these tests. I was more interested in the slowdown on ext4 (checked with the above mentioned program). Can you do such a test as well, and post resulting times with and without the patch? > Table 1. Reference platforms. > > ------------------------------------------------------------ > | | HP-UX/PA-RISC | HP-UX/Itanium | FreeBSD | > ------------------------------------------------------------ > | First run | 263405 usec | 202283 usec | 90 SECONDS | > ------------------------------------------------------------ > | Second run | 262253 usec | 172837 usec | 90 SECONDS | > ------------------------------------------------------------ > | Third run | 238465 usec | 238465 usec | 90 SECONDS | > ------------------------------------------------------------ > > It looks like FreeBSD is a clear outsider here. Note that FreeBSD > showed an almost liner depencence of the time spent in the > msync(MS_ASYNC) call on the file size. > > Table 2. The Qemu system. File size is 512M. > > --------------------------------------------------- > | | Before the patch | After the patch | > --------------------------------------------------- > | First run | 35 usec | 5852 usec | > --------------------------------------------------- > | Second run | 35 usec | 4444 usec | > --------------------------------------------------- > | Third run | 35 usec | 6330 usec | > --------------------------------------------------- Interesting. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/