[ILUG] Load avg and other randoms

From: Paul Jakma paul@clubi.ie
Date: Wed, 19 May 1999 00:18:27 +0100 (IST)

On Tue, 18 May 1999, Dave Wilson wrote:

  Hi all,

  Well, what *does* the load average really mean? :-)

load average is the average number of processes on the run queue over
the last minute, 5 minutes and 15 minutes respectively.

so if your load is one, then on average there was one process
ready to run over the last 1,5,15 mins. ie on average there was
always something running on computer, but there never was a backlog.

as long as your loadavg <= the number of cpu's in your system, then
everything's ok. if the loadavg goes above 1 on a single cpu machine
or two on a dual-cpu pc, then it means that there were more processes
ready to run than there were cpu resources, ie there were processes
'straining at the leash' but they had to wait a bit before they got
their go on the processor.

lot's of kernel activity, eg swapping, will cause your loadavg to go
up, as the kernel has to do things, which takes away cpu resources
from processes.

so loadavg = the avg length of the queue for cpu time.

(amazing how much you can waffle about loadavg's, isn't it?) :)

regards,
--
Paul Jakma
paul@clubi.ie	http://hibernia.clubi.ie
PGP5 key: http://www.clubi.ie/jakma/publickey.txt
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