From owner-freebsd-current@FreeBSD.ORG Fri Sep 16 16:21:23 2005 Return-Path: X-Original-To: current@freebsd.org 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 20BDF16A41F for ; Fri, 16 Sep 2005 16:21:23 +0000 (GMT) (envelope-from joseph.koshy@gmail.com) Received: from xproxy.gmail.com (xproxy.gmail.com [66.249.82.199]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3407743D49 for ; Fri, 16 Sep 2005 16:21:22 +0000 (GMT) (envelope-from joseph.koshy@gmail.com) Received: by xproxy.gmail.com with SMTP id i31so723142wxd for ; Fri, 16 Sep 2005 09:21:21 -0700 (PDT) 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:content-disposition:references; b=emqLnBMhcyhIb9t1ItU6UDCuuZ0OeSwWuGtSVRgtw20rfX/bgBuD2UxKWApjW54L5N8ZXKnwVYxaBl5/phgjadvNv3XwJp12WympbkpxRUwwwHZFO7sGJ2gfwIKX8CVwIwt36eIdGBTNN/17x91id1dqSKgTxkG7NbvoHXZ2M4M= Received: by 10.70.117.2 with SMTP id p2mr243087wxc; Fri, 16 Sep 2005 09:21:21 -0700 (PDT) Received: by 10.70.115.15 with HTTP; Fri, 16 Sep 2005 09:21:21 -0700 (PDT) Message-ID: <84dead720509160921732e7f96@mail.gmail.com> Date: Fri, 16 Sep 2005 21:51:21 +0530 From: Joseph Koshy To: Oliver Lehmann In-Reply-To: <20050915181238.54b16b4b.lehmann@ans-netz.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <20050914194612.15692485.lehmann@ans-netz.de> <43286E37.40203@samsco.org> <20050914222013.178dc4dc.lehmann@ans-netz.de> <84dead72050914135239514c49@mail.gmail.com> <20050915000053.448f251b.lehmann@ans-netz.de> <84dead7205091500152a7c25d1@mail.gmail.com> <20050915172005.072f4bdf.lehmann@ans-netz.de> <20050915181238.54b16b4b.lehmann@ans-netz.de> Cc: current@freebsd.org Subject: Re: low(er) disk performance with sched_4bsd then with sched_ule X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: joseph.koshy@gmail.com List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Sep 2005 16:21:23 -0000 jk> What happens if you use a kernel with 'options=20 jk> NO_ADAPTIVE_MUTEXES' ? ol> Hmm, that made it more worse ol> http://pofo.de/tmp/gprof.4bsd.2 >From the profile it appears that with adaptive mutexes turned off the kernel is spinning inside vm_pageout(). 41.1 vm_pageout [1] 25.0 _mtx_trylock [2] 5.1 smp_tlb_shootdown [3] Hmm ... the dd command line *did* ask for about approx 2 GB of zero-filled memory from the kernel while the machine has about 640M. I'm just not able to reproduce this kind of skewed profile on -current on a uniprocessor amd64 and on a P4 HT machine. Just as an off-chance: how upto-date is your kernel? In=20 particular, do you have the following fix:=20 "sys/vm/vm_pager.c:" revision 1.105.2.1 date: 2005/08/15 14:04:47; author: kan; state: Exp; lines: +1 -0 MFC: Do not use vm_pager_init() to initialize=20 vnode_pbuf_freecnt variable. vm_pager_init() is run before=20 required nswbuf variable has been set to correct value. This=20 caused system to run with single pbuf available for=20 vnode_pager. Handle both cluster_pbuf_freecnt and=20 node_pbuf_freecnt variableis in the same way. --=20 FreeBSD Volunteer, http://people.freebsd.org/~jkoshy