From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <46B8C382.1070106@tmr.com> Date: Tue, 07 Aug 2007 15:09:54 -0400 From: Bill Davidsen MIME-Version: 1.0 Subject: Re: [PATCH 00/23] per device dirty throttling -v8 References: <20070804070737.GA940@elte.hu> <20070804103347.GA1956@elte.hu> <20070804163733.GA31001@elte.hu> <46B4C0A8.1000902@garzik.org> <20070804191205.GA24723@lazybastard.org> <20070804192130.GA25346@elte.hu> <20070804211156.5f600d80@the-village.bc.nu> <20070804202830.GA4538@elte.hu> <20070804210351.GA9784@elte.hu> <20070804225121.5c7b66e0@the-village.bc.nu> In-Reply-To: <20070804225121.5c7b66e0@the-village.bc.nu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Alan Cox Cc: Ingo Molnar , J??rn Engel , Jeff Garzik , Linus Torvalds , Peter Zijlstra , linux-mm@kvack.org, Linux Kernel Mailing List , miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com, richard@rsk.demon.co.uk, david@lang.hm List-ID: Alan Cox wrote: >> i cannot over-emphasise how much of a deal it is in practice. Atime >> updates are by far the biggest IO performance deficiency that Linux has >> today. Getting rid of atime updates would give us more everyday Linux >> performance than all the pagecache speedups of the past 10 years, >> _combined_. >> >> it's also perhaps the most stupid Unix design idea of all times. Unix is >> really nice and well done, but think about this a bit: > > Think about the user for a moment instead. > > Do things right. The job of the kernel is not to "correct" for > distribution policy decisions. The distributions need to change policy. > You do that by showing the distributions the numbers. > > With a Red Hat on if we can move from /dev/hda to /dev/sda in FC7 then we > can move from atime to noatime by default on FC8 with appropriate release > note warnings and having a couple of betas to find out what other than > mutt goes boom. Is there really enough benefit between relatime and noatime to justify that? If atime doesn't get updated at all it *will* impact operations, and unless there's a real performance gain the path which provides at least nominal POSIX compliance seems best. Plauger's law of least astonishment. -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot -- 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