unix perfmon

who will return:
wingr0 ttyp2 Jan 7 03:27
dbhag0 ttyp3 Jan 17 23:55
ldavi0 ttyp4 Jan 19 15:49

Here is the syntax:
Usage:who [-rbtpludAasHTqRm] [am i]
[utmp_like_file]

r run level
b boot time
t time changes
p processes other than getty or users
l login processes
u useful information
d dead processes
A accounting information
a all (rbtpludA options)
s short form of who (no time since last
output or pid)
H print header
T status of tty (+ writable, - not writable,
x exclusive open, ? hung)
q quick who
R print host name

Good luck.

dennie

"rstatd" is more or less equivalent,

u can also use tools like vmstat,sar,iostat

to measure various performance parameters.

Good luck