Date: Sun, 20 Apr 2003 10:57:47 -0600 (CST) From: Ryan Thompson <ryan@sasknow.com> To: Paulo Roberto <nirv199@yahoo.com> Cc: freebsd-questions@freebsd.org Subject: Re: load averages Message-ID: <20030420104446.K68932-100000@ren.sasknow.com> In-Reply-To: <20030420162845.21400.qmail@web14902.mail.yahoo.com>
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Paulo Roberto wrote to freebsd-questions@freebsd.org: > Hello, Hi Paulo, > Is the "load averages" field in uptime/top in percentage?? No. The load averages represent the number of processes in the run queue (i.e., the number of processes that are ready to run, but must wait for CPU time). Load averages > 1.00 are normal. I haven't seen this discussion on here for awhile, so I'll explain further. Load averages are only loosely correlated with system performance. It is possible to have relatively high load averages, and still have a very responsive system. It is also possible to have load averages below 0.50 on a disk-bound machine, and have an unusable machine. (I've seen both). It is also possible to inadvertently write a fork bomb (in Perl) and watch them peak at about 600, and still manage to obtain a sort-of-responsive root login to kill all of the processes. (Uh.. I've *never* seen that happen). Again, load average is a function of the number of processes waiting for CPU time. *Not* of actual CPU utilization (which will often be quite a bit lower than 100%), or of overall resource utilization (disk, net, etc.) Use load averages for only a very rough sanity check. - Ryan -- Ryan Thompson <ryan@sasknow.com> SaskNow Technologies - http://www.sasknow.com 901-1st Avenue North - Saskatoon, SK - S7K 1Y4 Tel: 306-664-3600 Fax: 306-244-7037 Saskatoon Toll-Free: 877-727-5669 (877-SASKNOW) North America
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