From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH 00/23] per device dirty throttling -v8 From: Arjan van de Ven In-Reply-To: <20070805144645.GA28263@thunk.org> References: <20070803123712.987126000@chello.nl> <46B4E161.9080100@garzik.org> <20070804224706.617500a0@the-village.bc.nu> <200708050051.40758.ctpm@ist.utl.pt> <20070805014926.400d0608@the-village.bc.nu> <20070805144645.GA28263@thunk.org> Content-Type: text/plain Date: Sun, 05 Aug 2007 11:08:19 -0700 Message-Id: <1186337299.2777.19.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Theodore Tso Cc: Alan Cox , Claudio Martins , Jeff Garzik , Ingo Molnar , =?ISO-8859-1?Q?J=F6rn?= Engel , 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: > > In addition, big server boxes are usually not reading a huge *number* > of files per second. The place where you see this as a problem is (a) > compilation, thanks to huge /usr/include hierarchies (and here things > have gotten worse over time as include files have gotten much more > complex than in the early Unix days), and (b) silly desktop apps that > want to scan huge numbers of XML files or who want to read every > single image file on the desktop or in an open file browser window to > show c00l icons. Oh, and I guess I should include Maildir setups. > > If you are always reading from the same small set of files (i.e., a > database workload), then those inodes only get updated every 5 seconds > (the traditional/default metadata update sync time, as well as the > default ext3 journal update time), it's no big deal. Or if you are > running a mail server, most of the time the mail queue files are > getting updated anyway as you process them, and usually the mail is > delivered before 5 seconds is up anyway. it's just one of those things that get compounded with journaling filesystems though..... a single async write that happens "sometime in the future" is one thing... having a full transaction (which acts as barrier and synchronisation point) is something totally worse. -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.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