From owner-freebsd-hackers@FreeBSD.ORG Sun Jul 6 17:55:35 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 1B52FC3B for ; Sun, 6 Jul 2014 17:55:35 +0000 (UTC) Received: from systemdatarecorder.org (ec2-54-246-96-61.eu-west-1.compute.amazonaws.com [54.246.96.61]) (using TLSv1.1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client CN "localhost", Issuer "localhost" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id AB7B9260D for ; Sun, 6 Jul 2014 17:55:33 +0000 (UTC) Received: from nereid (84-253-211-213.bb.dnainternet.fi [84.253.211.213]) (authenticated bits=0) by systemdatarecorder.org (8.14.4/8.14.4/Debian-2ubuntu2.1) with ESMTP id s66HrtNv005846 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 6 Jul 2014 17:53:56 GMT Date: Sun, 6 Jul 2014 20:55:25 +0300 From: Stefan Parvu To: Konstantin Belousov Subject: Re: run-queue length question Message-Id: <20140706205525.2b17295699db832fe198de8c@systemdatarecorder.org> In-Reply-To: <20140706123359.GD93733@kib.kiev.ua> References: <20140706143212.3d22d0adfa5dece52de203a3@systemdatarecorder.org> <20140706123359.GD93733@kib.kiev.ua> Organization: systemdatarecorder.org X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.22; amd64-portbld-freebsd11.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 Jul 2014 17:55:35 -0000 > It is the Linux which follows the traditional definition of the load, > by counting running, ready to run and 'blocked on the fast i/o' processes > as adding to the load average. Also, I remember that FreeBSD up to 4.x > followed this definition. If I understood right, the classic example follows Solaris SunOS 2.x until Solaris 10 where rq does not include any iowait processes. Hmmm... for sure Solaris 7,8,9 were talking rq with no iowait. I dont remember now about Solaris 10 but I think it does not add iowait to the rq. And if I recall right Linux 2.4 had similar behaviour as Solaris. I dont recall FreeBSD but I recall sometime back there was no load average metric into kernel. I need to read src code for it. > Sometime during the 5.x rewrites the load was redefined to only count > running + ready to run threads, which is the current definition, used by LA. I see. Well Im happy today at least to see FreeBSD having a proper definition for rq comparative to Linux. Gunther [1] explains in details why rq does include running and runnable only, very well. Thanks a lot [1] - Analyzing Computer System Performance with Perl::PDQ 2nd edition http://www.perfdynamics.com/books.html -- Stefan Parvu