From owner-freebsd-hackers@FreeBSD.ORG Tue Feb 15 22:27:57 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 616EA16A4DF for ; Tue, 15 Feb 2005 22:27:57 +0000 (GMT) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.197]) by mx1.FreeBSD.org (Postfix) with ESMTP id EFFF943D41 for ; Tue, 15 Feb 2005 22:27:56 +0000 (GMT) (envelope-from bosko.milekic@gmail.com) Received: by wproxy.gmail.com with SMTP id 69so879235wra for ; Tue, 15 Feb 2005 14:27:54 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:references; b=k1cMeo6Mc650In5rPKStLQRYno9e+8n+tPcU+f60wdOSra+Y68pz/3pbVWTIUNxV7Ywudu1O0SJl+UVkbfmNNkqrvDbV55dITAwrGk4d45ehcZVQFfGrdp3iePBceMtnqvzvs45q+5ATIdT2ycdyhpfHzc1GeKRwzr/MOQ8KhVY= Received: by 10.54.5.57 with SMTP id 57mr111280wre; Tue, 15 Feb 2005 14:27:53 -0800 (PST) Received: by 10.54.24.68 with HTTP; Tue, 15 Feb 2005 14:27:51 -0800 (PST) Message-ID: Date: Tue, 15 Feb 2005 17:27:51 -0500 From: Bosko Milekic To: Max Laier In-Reply-To: <200502151655.09800.max@love2party.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit References: <02266ed294653cda2452e7ac0a713c2c@sarenet.es> <200502151655.09800.max@love2party.net> X-Mailman-Approved-At: Wed, 16 Feb 2005 12:56:18 +0000 cc: freebsd-hackers@freebsd.org cc: Borja Marcos Subject: Re: MBUF statistics X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: Bosko Milekic List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Feb 2005 22:27:57 -0000 On Tue, 15 Feb 2005 16:54:52 +0100, Max Laier wrote: > On Tuesday 15 February 2005 12:38, Borja Marcos wrote: > > Hello, > > > > Looking at the mbuf statistics available in FreeBSD 4 and FreeBSD 5 I > > can see that the statistics available in FreeBSD 5 are, surprisingly, > > much less comprehensive. Is there any other place where I can find out > > how many mbuf requests have been done, how many of them have waited, > > how many have failed, etc? > > I use "$vmstat -z | grep Mbuf". The netstat -m output is broken, because > fixing this would impose an additional atomic operation on each alloc/free > which is a real performance killer. Yeah, unfortunately statistics are too hard to do completely correctly right now (too hard on performance, that is). To make things worse, the more involved UMA zone design used for Mbuf and Cluster allocations means that some of the UMA zone statistics you get with "vmstat -z" are not entirely accurate. The UMA zone statistics code needs to be changed to accomodate this structure, but in addition to that a way to make statistics gathering cheaper would be nice, because currently doing a 'vmstat -z' is really terrible for performance. Which reminds me... those of you doing benchmarks, please don't run 'vmstat -z' while you're doing them, it might skew/pessimize your results. -- Bosko Milekic - If I were a number, I'd be irrational. Contact Info: http://bmilekic.unixdaemons.com/contact.txt