From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264919AbUHAC4R (ORCPT ); Sat, 31 Jul 2004 22:56:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264965AbUHAC4R (ORCPT ); Sat, 31 Jul 2004 22:56:17 -0400 Received: from waste.org ([209.173.204.2]:36066 "EHLO waste.org") by vger.kernel.org with ESMTP id S264919AbUHAC4Q (ORCPT ); Sat, 31 Jul 2004 22:56:16 -0400 Date: Sat, 31 Jul 2004 21:55:38 -0500 From: Matt Mackall To: Lee Revell Cc: jackit-devel , Ingo Molnar , linux-kernel Subject: Re: Statistical methods for latency profiling Message-ID: <20040801025538.GY5414@waste.org> References: <1091251357.1677.116.camel@mindpipe> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1091251357.1677.116.camel@mindpipe> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 31, 2004 at 01:22:37AM -0400, Lee Revell wrote: > Hey, > > Recently Ingo Molnar asked in one of the voluntary-preempt threads for > the minimum and average scheduling delay reported by jackd. JACK does > not currently maintain these statistics. > > I realized that the distribution of maximum latencies reported on each > process cycle is fairly normally distributed. This is not at all what I would expect. Instead, I'd expect to see something like a gamma distribution, where we have everything clustered down close to zero, but with a very long tail in the positive direction falling off exponentially and obviously a hard limit on the other side.. -- Mathematics is the supreme nostalgia of our time.