From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265060AbUHADXp (ORCPT ); Sat, 31 Jul 2004 23:23:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265087AbUHADXo (ORCPT ); Sat, 31 Jul 2004 23:23:44 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:28094 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S265060AbUHADXm (ORCPT ); Sat, 31 Jul 2004 23:23:42 -0400 Subject: Re: [Jackit-devel] Re: Statistical methods for latency profiling From: Lee Revell To: Matt Mackall Cc: jackit-devel , Ingo Molnar , linux-kernel In-Reply-To: <20040801025538.GY5414@waste.org> References: <1091251357.1677.116.camel@mindpipe> <20040801025538.GY5414@waste.org> Content-Type: text/plain Message-Id: <1091330650.20819.163.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Sat, 31 Jul 2004 23:24:11 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2004-07-31 at 22:55, Matt Mackall wrote: > 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.. Right, it is a lot closer to a gamma distribution. It's been years since I have used any of this, and I took stat for psych majors, vs stat for engineers. I was a lot more interested in playing Doom at the time... This looks interesting: http://www.itl.nist.gov/div898/handbook/eda/section3/ppccplot.htm http://www.itl.nist.gov/div898/handbook/eda/section4/eda4291.htm I will have some numbers soon. Lee