From owner-freebsd-hackers@FreeBSD.ORG Fri May 12 07:37:19 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org 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 2871216A4E5 for ; Fri, 12 May 2006 07:37:19 +0000 (UTC) (envelope-from peterjeremy@optushome.com.au) Received: from mail26.syd.optusnet.com.au (mail26.syd.optusnet.com.au [211.29.133.167]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2B75343FF0 for ; Fri, 12 May 2006 07:17:23 +0000 (GMT) (envelope-from peterjeremy@optushome.com.au) Received: from turion.vk2pj.dyndns.org (c220-239-19-236.belrs4.nsw.optusnet.com.au [220.239.19.236]) by mail26.syd.optusnet.com.au (8.12.11/8.12.11) with ESMTP id k4C7HBeY024752 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Fri, 12 May 2006 17:17:21 +1000 Received: from turion.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by turion.vk2pj.dyndns.org (8.13.6/8.13.6) with ESMTP id k4C7HBpH000901; Fri, 12 May 2006 17:17:11 +1000 (EST) (envelope-from peter@turion.vk2pj.dyndns.org) Received: (from peter@localhost) by turion.vk2pj.dyndns.org (8.13.6/8.13.6/Submit) id k4C7HBlb000900; Fri, 12 May 2006 17:17:11 +1000 (EST) (envelope-from peter) Date: Fri, 12 May 2006 17:17:11 +1000 From: Peter Jeremy To: Iasen Kostov Message-ID: <20060512071711.GA714@turion.vk2pj.dyndns.org> Mail-Followup-To: Peter Jeremy , Iasen Kostov , FreeBSD Hackers References: <1147264089.51661.10.camel@DraGoN.OTEL.net> <1147264379.51661.14.camel@DraGoN.OTEL.net> <1147265038.51661.19.camel@DraGoN.OTEL.net> <1147361590.33341.19.camel@DraGoN.OTEL.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1147361590.33341.19.camel@DraGoN.OTEL.net> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.11 Cc: FreeBSD Hackers Subject: Re: Heavy system load by pagedaemon X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 May 2006 07:37:27 -0000 On Thu, 2006-May-11 18:33:10 +0300, Iasen Kostov wrote: > And another odd thing (to me atleast): > >#:> vmstat -s | grep "daemon\|fault" > 0 page daemon wakeups > 0 pages examined by the page daemon > 4992608 copy-on-write faults > 29021 copy-on-write optimized faults > 75167 intransit blocking page faults > 66956262 total VM faults taken > 0 pages freed by daemon > >Acording to vmstat pagedaemon has never been awake. 'page daemon wakeups' counts the number of times that the pagedaemon is woken up due to a page shortage. It does not include the 5-sec wakeups. How about posting a complete 'vmstat -s'. A look at the code suggests that vm_pageout_page_stats() thinks there's a page shortage (since that's the only piece of code that will actually do anything if page daemon wakeups is zero). >Kamal R. Prasad suggested that "Belady's anomaly" might occur. If it's >true or possible what could be done about this ? "Belady's anomaly" can only occur if paging really happens. -- Peter Jeremy