From owner-freebsd-performance@FreeBSD.ORG Tue Jun 13 18:43:40 2006 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1A63216A47B for ; Tue, 13 Jun 2006 18:43:40 +0000 (UTC) (envelope-from danial_thom@yahoo.com) Received: from web33314.mail.mud.yahoo.com (web33314.mail.mud.yahoo.com [68.142.206.129]) by mx1.FreeBSD.org (Postfix) with SMTP id 1D05B43D48 for ; Tue, 13 Jun 2006 18:43:37 +0000 (GMT) (envelope-from danial_thom@yahoo.com) Received: (qmail 60231 invoked by uid 60001); 13 Jun 2006 18:43:36 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=DyK7tmlOn0MN29p52zFolf4agqne+9Xi5q4ilu2ic25Yg1fFrVAj6uYFNaJ2op1xqiA9w2JUiFZ/RyXGHCEmXqte39QyyzU+Qq0pWfSd/OTPjQ1vCYKZa41g5uWno3Z3rEKQC9XxbeYhN+c/Y5X6EVVYGpMBq61GrBIav7fZXVU= ; Message-ID: <20060613184336.60229.qmail@web33314.mail.mud.yahoo.com> Received: from [65.34.182.15] by web33314.mail.mud.yahoo.com via HTTP; Tue, 13 Jun 2006 11:43:36 PDT Date: Tue, 13 Jun 2006 11:43:36 -0700 (PDT) From: Danial Thom To: Robert Watson In-Reply-To: <20060613193040.O26068@fledge.watson.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: freebsd-performance@freebsd.org, David Xu Subject: Re: Initial 6.1 questions X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: danial_thom@yahoo.com List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 Jun 2006 18:43:40 -0000 --- Robert Watson wrote: > > On Tue, 13 Jun 2006, Danial Thom wrote: > > > Maybe someone can explain this output. The > top line shows 99.6%idle. Is it > > just showing CPU 0s stats on the top line? > > Two types of measurements are taken: sampled > ticks regarding whether the > system as a while is in {user, nice, system, > intr, idle}, and then sampling > for individual processes. Right now, the > system measurements are kept in a > simple array of tick counters called cp_time. > John Baldwin and others have > changes that make these tick counters per-CPU. > The lines at the top of > top(1)'s output are derived from those tick > counters. Ticks are measured on > each CPU, so those are a summary across all > CPUs. To add cpustat support, we > need to merge John's patch to make cp_time > per-CPU (ie., different counters > for different CPUs) and teach the userland > tools to retrieve them. When you > run top you'll notice that it adjusts the > measurements each refresh. In > effect, what it's doing is sampling the change > in tick counts over the window, > pulling down the new values and calculating the > percentages of ticks in each > "bucket" in the last window. That doesn't explain why the Top line shows 99.6% idle, but the cpu idle threads are showing significant usage. I'm getting a constant 6000 Interrupts / Second on my em controller, yet top jumps all over the place; sitting at 99% idle for 10 seconds, then jumping to 50%, then somewhere in between. It seems completely unreliable. The load I'm applying is constant. DT __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com