From owner-freebsd-current Wed Feb 5 1: 6:13 2003 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1CC8737B401; Wed, 5 Feb 2003 01:06:12 -0800 (PST) Received: from vador.skynet.be (vador.skynet.be [195.238.3.236]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3E2FD43FA7; Wed, 5 Feb 2003 01:06:11 -0800 (PST) (envelope-from brad.knowles@skynet.be) Received: from [10.0.1.2] (ip-26.shub-internet.org [194.78.144.26] (may be forged)) by vador.skynet.be (8.12.7/8.12.7/Skynet-OUT-2.21) with ESMTP id h1595uPU011546; Wed, 5 Feb 2003 10:05:57 +0100 (MET) (envelope-from ) Mime-Version: 1.0 X-Sender: bs663385@pop.skynet.be Message-Id: In-Reply-To: <35259.1044435254@critter.freebsd.dk> References: <35259.1044435254@critter.freebsd.dk> Date: Wed, 5 Feb 2003 10:05:11 +0100 To: phk@freebsd.org From: Brad Knowles Subject: Re: Preview: GEOMs statistics code. Cc: Brad Knowles , "Greg 'groggy' Lehey" , current@freebsd.org Content-Type: text/plain; charset="us-ascii" ; format="flowed" Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG At 9:54 AM +0100 2003/02/05, phk@freebsd.org wrote: >> My understanding was that a disk is 100% busy, if the heads are >>constantly moving to and fro, and there is no period of time when >>they aren't being yanked around. In other words, it would be 100% if >>there is always at least one outstanding request. > > Works for me, I'll try if I can instrument that cheaply. I should be heading off to the office here shortly. Let me see if I can quote the relevant sections of the iostat man page for Solaris, with the hope that they will be able to explain more accurately and clearly just exactly what it is that they measure and what it means. > I currently use binuptime() which means that the resolution is whatever > the system provides, which means better than 1 microsecond on all current > platforms. > > The counters are updated in real time, so it's up to you how often you > read them. So, we're talking about some fairly significant modifications to iostat to get it to poll these values and be able to create some averages that it can report. > Well, "tracelog" is simply my word for the concept of recording > each and every transaction and run it through some kind of analysis > afterwards. Ahh, I see. Thanks again! -- Brad Knowles, "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, Historical Review of Pennsylvania. GCS/IT d+(-) s:+(++)>: a C++(+++)$ UMBSHI++++$ P+>++ L+ !E-(---) W+++(--) N+ !w--- O- M++ V PS++(+++) PE- Y+(++) PGP>+++ t+(+++) 5++(+++) X++(+++) R+(+++) tv+(+++) b+(++++) DI+(++++) D+(++) G+(++++) e++>++++ h--- r---(+++)* z(+++) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message