*BSD News Article 70787


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From: jscholvi@bert.eecs.uic.edu (John Scholvin)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Q: What exactly does the time command tell me?
Date: 12 Jun 1996 11:33:35 -0500
Organization: University of Illinois at Chicago
Lines: 33
Message-ID: <4pmrgv$6kv@bert.eecs.uic.edu>
NNTP-Posting-Host: bert.eecs.uic.edu


Hi, everyone.

The subject about covers it: I'm running some fairly long simulations for my
master's thesis, and I need to know how long it's taking them to run. The
time(1) command prints out three things: "real" time, "user" time, and
"system" time. I've gathered that "real" time is wall clock time, and that
"system" time is the amount of time the process in question spends in
kernel.  I would think that the "user" time is the number I'm interested in,
how much time the processor is actually spending on my program, right?

The problem is that the user number is sometimes much less than the real
number, and the computer isn't really doing much else. For example, on one
run I got

21935.54 real  2866.26 user  28.19 sys

This is strange...there are about 5 hours unaccounted for there, and this
was on an overnight run on a system with *very* little else going on. I
mean, basically nothing except xperfmon++ and xclock. I'm the only user, the
computer is not on a network, and I walk away while it's running. Is
xperfmon++ the guilty party? Could it be the screen saver, beforelight?
Am I confused? :)

Specifics: FreeBSD 2.0.5 on a Gateway 2000 4DX2-66 with 16MB RAM and a swap
space of 64MB.

Thanks to everyone on the FreeBSD team for providing such a solid platform
for me to develop this monster on!
-- 
John Scholvin                        i'm the number on your kitchen door
jscholvi@eecs.uic.edu                i'm the baseball team from baltimore
http://www.eecs.uic.edu/~jscholvi/     --buffalo tom