From owner-freebsd-performance@FreeBSD.ORG Tue Jun 13 19:04:24 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 1503016A41B; Tue, 13 Jun 2006 19:04:24 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 677EA43D49; Tue, 13 Jun 2006 19:04:20 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [10.10.3.185] ([69.15.205.254]) (authenticated bits=0) by pooker.samsco.org (8.13.4/8.13.4) with ESMTP id k5DJ4A1S068353; Tue, 13 Jun 2006 13:04:16 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <448F0C20.3090800@samsco.org> Date: Tue, 13 Jun 2006 13:04:00 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.12) Gecko/20060206 X-Accept-Language: en-us, en MIME-Version: 1.0 To: danial_thom@yahoo.com References: <20060613184336.60229.qmail@web33314.mail.mud.yahoo.com> In-Reply-To: <20060613184336.60229.qmail@web33314.mail.mud.yahoo.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=0.0 required=3.8 tests=none autolearn=failed version=3.1.1 X-Spam-Checker-Version: SpamAssassin 3.1.1 (2006-03-10) on pooker.samsco.org Cc: freebsd-performance@freebsd.org, Robert Watson , David Xu Subject: Re: Initial 6.1 questions X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 Jun 2006 19:04:24 -0000 Danial Thom wrote: > > --- 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 Be aware that there was a significant change made to if_em in 7-CURRENT in Jan 2006 to improve load performance. It'll probably get backported for 6.2, but you might consider looking at it before you make up your mind on 6.1 performance. Sscott