From owner-freebsd-performance@FreeBSD.ORG Thu Jun 14 11:47:44 2007 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 87B5E16A41F for ; Thu, 14 Jun 2007 11:47:44 +0000 (UTC) (envelope-from thomas@bsdunix.ch) Received: from conversation.bsdunix.ch (ns1.bsdunix.ch [82.220.1.90]) by mx1.freebsd.org (Postfix) with ESMTP id 4CE5D13C480 for ; Thu, 14 Jun 2007 11:47:44 +0000 (UTC) (envelope-from thomas@bsdunix.ch) Received: from localhost (localhost.bsdunix.ch [127.0.0.1]) by conversation.bsdunix.ch (Postfix) with ESMTP id 48C1C5DBB; Thu, 14 Jun 2007 13:29:01 +0200 (CEST) X-Virus-Scanned: by amavisd-new at mail.bsdunix.ch Received: from conversation.bsdunix.ch ([127.0.0.1]) by localhost (conversation.bsdunix.ch [127.0.0.1]) (amavisd-new, port 10024) with LMTP id GWfIvxWqjTgY; Thu, 14 Jun 2007 13:29:00 +0200 (CEST) Received: from 192.168.1.102.local.home (home.bsdunix.ch [82.220.17.23]) by conversation.bsdunix.ch (Postfix) with ESMTP id 45A595DB1; Thu, 14 Jun 2007 13:29:00 +0200 (CEST) Message-ID: <46712605.5090907@bsdunix.ch> Date: Thu, 14 Jun 2007 13:27:01 +0200 From: Thomas Vogt User-Agent: Thunderbird 2.0.0.0 (Macintosh/20070326) MIME-Version: 1.0 To: NOC Meganet References: <4671118D.1040404@bsdunix.ch> <200706140806.05674.tec@mega.net.br> In-Reply-To: <200706140806.05674.tec@mega.net.br> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Thu, 14 Jun 2007 11:55:29 +0000 Cc: freebsd-performance@freebsd.org Subject: Re: PAPI in the ports 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: Thu, 14 Jun 2007 11:47:44 -0000 Hi NOC Meganet wrote: > On Thursday 14 June 2007 06:59:41 Thomas Vogt wrote: >> Hi >> >> Thats sounds nice. You wrote "The goal of the PmcTools project is to >> provide FreeBSD's developers and system administrators with >> non-intrusive, low-overhead and innovative ways of measuring and >> analysing system performance" your website. Have you ever measured the >> performance impact of such tools? >> >> I'm interested to run such tool on production machines in the future but >> only if the performance impact isn't that high. >> > > Hi > ... even if the tool (whatever it is) does not require much system resources > it triggers processes in order to measure their or the system's performance. > So long as you do not push the system to or over the edge you might not get > valuable numbers. So I mean, any performance measuring does or must stress > the system. That is at least my understanding. So probably running > performance tests on a production server is not the very best idea. Yes you're right. But to have a such feature on a production system is nice if you have to debug issues. If I get a problem I can easily debug it without to simulate everything in the lab. It's not that I want to run such features 24/7. But perhaps "options HWPMC_HOOKS" in the kernel enables some hooks which could cause performance penalties even if I don't actively use such feature very often. Like many other debug options in the kernel. I don't know. Regards, Tom