From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: Tracking actual disk write sources instead of flush thread Date: Sun, 27 Apr 2014 20:27:56 -0700 Message-ID: <87y4yqku9v.fsf@tassilo.jf.intel.com> References: <534DE477.5080904@ubuntu.com> <20140416140147.GA15429@linux.intel.com> <534E9E9D.5030600@ubuntu.com> <4C30833E5CDF444D84D942543DF65BDA625F51A9@G4W3303.americas.hpqcorp.net> <534EC964.6080702@ubuntu.com> <4C30833E5CDF444D84D942543DF65BDA625F5246@G4W3303.americas.hpqcorp.net> <534ED9B8.9090605@ubuntu.com> <20140423134805.GB13050@linux.intel.com> <535816E7.2070106@ubuntu.com> <68A83B3D-D029-4863-B9D9-2BD9894FDFDC@dilger.ca> Mime-Version: 1.0 Content-Type: text/plain Cc: Phillip Susi , Matthew Wilcox , "Zuckerman\, Boris" , "linux-fsdevel\@vger.kernel.org" To: Andreas Dilger Return-path: Received: from mga09.intel.com ([134.134.136.24]:26590 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492AbaD1D14 (ORCPT ); Sun, 27 Apr 2014 23:27:56 -0400 In-Reply-To: <68A83B3D-D029-4863-B9D9-2BD9894FDFDC@dilger.ca> (Andreas Dilger's message of "Wed, 23 Apr 2014 17:19:25 -0600") Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Andreas Dilger writes: > I think that adding a pointer or integer per page would meet resistance, > but I think it is pretty reasonable to track this on a per-inode > basis. That's a really bad hot cache line in the making. > It is fairly uncommon to have multiple threads writing to the same file, > and I would guess it is vanishingly rare that different applications are > writing to the same file at one time. Sounds like a bad assumption to me. Likely would be a scalability disaster. -Andi -- ak@linux.intel.com -- Speaking for myself only