From owner-freebsd-stable@FreeBSD.ORG Mon Oct 15 22:32:49 2007 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C806616A41A for ; Mon, 15 Oct 2007 22:32:49 +0000 (UTC) (envelope-from bright@elvis.mu.org) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.freebsd.org (Postfix) with ESMTP id 9AD4D13C448 for ; Mon, 15 Oct 2007 22:32:49 +0000 (UTC) (envelope-from bright@elvis.mu.org) Received: by elvis.mu.org (Postfix, from userid 1192) id 3562E1A4D81; Mon, 15 Oct 2007 15:08:36 -0700 (PDT) Date: Mon, 15 Oct 2007 15:08:36 -0700 From: Alfred Perlstein To: William LeFebvre Message-ID: <20071015220836.GO31826@elvis.mu.org> References: <008801c80e66$7be49490$0c00a8c0@Artem> <471367F2.7050303@lefebvre.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <471367F2.7050303@lefebvre.org> User-Agent: Mutt/1.4.2.3i Cc: freebsd-stable@freebsd.org Subject: Re: Question about 'top' values on memory usage X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 Oct 2007 22:32:49 -0000 * William LeFebvre [071015 06:49] wrote: > > Unfortunately, freebsd does not appear to track the amount of shared > virtual memory for each process. It could be obtained by walking > through all the pages in a process's vm map, but that would really slow > top down. I don't know of any freebsd utility that would give that > information for an individual process. But hey, if it's out there > somewhere where it is easy to grab, I would be very happy to add it to top. Or this could be properly accounted for when the map is updated? > Personally, based on my experience, I would be more concerned with the > amount of available cpu cycles than memory. In my experience, once you > run out of idle time on a web server you have exceeded its capacity to > serve pages. In that situation it doesn't matter how many httpd > processes there are, the system is still not able to keep up with > demand. And that will probably happen before the system starts > thrashing from limited memory. Bill, I would have to differ with you based on personal experience, I've almost never run out of cpu on a webserver, typically it's the RAM that gets blown out. Once the server starts to page, you typically wind up with a cascade failure and the box just goes ... belly up. I would worry about ram. Typically the best way to scale a box is to load it and keep running more httpds until "something happens" or you reach enough httpd to service your load, at that point if "something happens" (ie the box tanks) you add more ram. -- - Alfred Perlstein