From owner-freebsd-questions Thu Jul 8 19:42:28 1999 Delivered-To: freebsd-questions@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id A9DE014D0C for ; Thu, 8 Jul 1999 19:42:20 -0700 (PDT) (envelope-from root@implode.root.com) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id TAA04489; Thu, 8 Jul 1999 19:41:39 -0700 (PDT) Message-Id: <199907090241.TAA04489@implode.root.com> To: "Andrew Johns" Cc: "=?iso-8859-1?Q?Alejandro_Ram=EDrez?=" , freebsd-questions@FreeBSD.ORG Subject: Re: Uptime basics!!! In-reply-to: Your message of "Fri, 09 Jul 1999 11:50:04 +1000." <002201bec9ad$5d7d4ad0$4001a8c0@tasajohns.turnaround.com.au> From: David Greenman Reply-To: dg@root.com Date: Thu, 08 Jul 1999 19:41:39 -0700 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >The load average figures are an indication of the number of processors >(ie:CPU's) that would be kept 100% busy by the current processes >(ie:programs) running on the machine. > >So, load average = 1 implies you've got a busy machine which is using >100% of it's CPU(s) (irrespective of how many CPU's you have). If the >load goes to 5.3, then you are running enough processes to keep 5 CPU's >100% busy and one more CPU at 30%. Uh, no, that is not what the load average means. The load average is a composite number that includes both runnable processes and processes that are blocked in a short term wait (usually disk I/O). This means that for machines that are doing heavy disk I/O, the load average could be quite high even when the CPU is 95% idle. On wcarchive, for example, the load average typically runs around 40-50 with 50% CPU idle time. This may sound high, but there are 38 disk drives on the machine, so although the drives are fairly busy, the I/O is spread out over all of them - keeping the interactive response time low and overall performance quite high. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project - http://www.freebsd.org Creator of high-performance Internet servers - http://www.terasolutions.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message