2 So What Is It?
So, exactly what is this thing called load average that is reported by all these various commands? Let's look at the official UNIX documentation. 2.1 The man Page
[pax:~]% man "load average"
No manual entry for load average
defiant:~ ben$ apropos 'load average'
getloadavg(3) - get system load averages
loads.d(1m) - print load averages. Uses DTrace
xload(1) - system load average display for X
defiant:~ ben$ man getloadavg
GETLOADAVG(3) BSD Library Functions Manual GETLOADAVG(3)
NAME getloadavg -- get system load averages
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS #include <stdlib.h>
int getloadavg(doubleloadavg[], intnelem);
DESCRIPTION
The getloadavg() function returns the number of processes in the system
run queue averaged over various periods of time. Up to nelem samples are
retrieved and assigned to successive elements of loadavg[]. The system
imposes a maximum of 3 samples, representing averages over the last 1, 5,
and 15 minutes, respectively.
DIAGNOSTICS
If the load average was unobtainable, -1 is returned; otherwise, the num-
ber of samples actually retrieved is returned.
SEE ALSO
uptime(1), kvm_getloadavg(3), sysctl(3)
HISTORY
The getloadavg() function appeared in 4.3BSD-Reno.