From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <46DD2760.3040505@wldelft.nl> Date: Tue, 04 Sep 2007 11:37:36 +0200 From: Leroy van Logchem MIME-Version: 1.0 Subject: Re: huge improvement with per-device dirty throttling References: <1187764638.6869.17.camel@hannibal> <20070822124736.GQ13915@v2.random> In-Reply-To: <20070822124736.GQ13915@v2.random> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Andi Kleen , "Jeffrey W. Baker" , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Andrea Arcangeli wrote: > On Wed, Aug 22, 2007 at 01:05:13PM +0200, Andi Kleen wrote: >> Ok perhaps the new adaptive dirty limits helps your single disk >> a lot too. But your improvements seem to be more "collateral damage" @) >> >> But if that was true it might be enough to just change the dirty limits >> to get the same effect on your system. You might want to play with >> /proc/sys/vm/dirty_* > > The adaptive dirty limit is per task so it can't be reproduced with > global sysctl. It made quite some difference when I researched into it > in function of time. This isn't in function of time but it certainly > makes a lot of difference too, actually it's the most important part > of the patchset for most people, the rest is for the corner cases that > aren't handled right currently (writing to a slow device with > writeback cache has always been hanging the whole thing). Self-tuning > static sysctl's. The last years we needed to use very small values for dirty_ratio and dirty_background_ratio to soften the latency problems we have during sustained writes. Imo these patches really help in many cases, please commit to mainline. -- Leroy -- 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