From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750913Ab0JOEAn (ORCPT ); Fri, 15 Oct 2010 00:00:43 -0400 Received: from outmail148114.authsmtp.net ([62.13.148.114]:53502 "EHLO outmail148114.authsmtp.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750780Ab0JOEAl (ORCPT ); Fri, 15 Oct 2010 00:00:41 -0400 X-Greylist: delayed 1200 seconds by postgrey-1.27 at vger.kernel.org; Fri, 15 Oct 2010 00:00:41 EDT From: Ben Pfaff To: Randy Dunlap Cc: Bruno Randolf , linux-kernel@vger.kernel.org, akpm Subject: Re: [PATCH] Add generic exponentially weighted moving average function References: <20101006093225.8739.14012.stgit@tt-desk> <20101012173352.0a458c24.randy.dunlap@oracle.com> Reply-To: Ben Pfaff Date: Thu, 14 Oct 2010 20:40:24 -0700 In-Reply-To: <20101012173352.0a458c24.randy.dunlap@oracle.com> (Randy Dunlap's message of "Tue, 12 Oct 2010 17:33:52 -0700") Message-ID: <87y6a0unrr.fsf@benpfaff.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Server-Quench: f3967a4f-d80d-11df-80b9-0022640b883e X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCdwYQ8QAVZfSBwy AC4CFCFJRwtjIQdD FxoeKRdbOF4EFVgQ JB8HaX1YLBpGHQgB E2YPUVBUWl92F2Rz dQtVcwFVfEhOXRpo VUpMXVMcSwweAklh YX4eVBFxdwAIcHpz ZQg0XXldWxV+I1sp Sk4ACGwHMTF9YGBN WV1YdwFWdgdKLBdN aQUxNiYHcQ5nFx4T Pzp7Fjw9dTpSLilP QwpFIEIKRkAGGCI9 ThQGDH0wEEwKRzk+ I1QjLUAdGklZO1s/ K1IuVBoWLhkZFgxZ GSkA X-Authentic-SMTP: 61633331373532.1015:706 X-AuthFastPath: 255 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Randy Dunlap writes: > On Wed, 06 Oct 2010 18:32:25 +0900 Bruno Randolf wrote: > >> This adds a generic exponentially weighted moving average function. This >> implementation makes use of a structure which keeps a scaled up internal >> representation to reduce rounding errors. >> >> The idea for this implementation comes from the rt2x00 driver (rt2x00link.c) >> and i would like to use it in several places in the mac80211 and ath5k code. > > I guess I don't understand "exponentially weighted" or why that would > be desirable. Please try to explain (briefly). I wrote up a fairly non-brief explanation of exponentially weighted moving averages a few years ago: http://www.stanford.edu/class/cs140/projects/pintos/pintos_7.html#SEC134 -- Ben Pfaff http://benpfaff.org