From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 4/4] writeback: reduce per-bdi dirty threshold ramp up time Date: Tue, 24 May 2011 14:41:58 +0200 Message-ID: <1306240918.2497.53.camel@laptop> References: <20110413220444.GF4648@quack.suse.cz> <20110413233122.GA6097@localhost> <20110413235211.GN31057@dastard> <20110414002301.GA9826@localhost> <20110414151424.GA367@localhost> <20110414181609.GH5054@quack.suse.cz> <20110415034300.GA23430@localhost> <20110415143711.GA17181@localhost> <20110415221314.GE5432@quack.suse.cz> <1302942809.2388.254.camel@twins> <20110418145929.GH5557@quack.suse.cz> <1306239869.2497.50.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Wu Fengguang , Dave Chinner , Andrew Morton , Richard Kennedy , Hugh Dickins , Rik van Riel , LKML , Linux Memory Management List , "linux-fsdevel@vger.kernel.org" To: Jan Kara Return-path: Received: from casper.infradead.org ([85.118.1.10]:41674 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754779Ab1EXMii (ORCPT ); Tue, 24 May 2011 08:38:38 -0400 Received: from j77219.upc-j.chello.nl ([24.132.77.219] helo=dyad.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.76 #1 (Red Hat Linux)) id 1QOqsu-0001hM-70 for linux-fsdevel@vger.kernel.org; Tue, 24 May 2011 12:38:52 +0000 In-Reply-To: <1306239869.2497.50.camel@laptop> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, 2011-05-24 at 14:24 +0200, Peter Zijlstra wrote: > Again, if we then measure t in the same events as x, such that: > > t = \Sum_i x_i > However, if you start measuring t differently that breaks, and the > result is no longer normalized and thus not suitable as a proportion. Ah, I made a mistake there, your proposal would keep the above relation true, but the discrete periods t_i wouldn't be uniform. So disregard the non normalized criticism.