 | | | computing load averages | computing load averages 2005-05-19 - By Ben Russo
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Shragai, Yaron wrote:
> Hello,
> How are load averages computed for the top command and the /proc/loadavg
> file? Where do the numbers come from?
>
> Thanks,
> Yaron
>
cat /proc/loadavg
These are numbers internal to the kernel.
They are 5, 10 and 15 minute average values
of the number of processes that are in a "run" state at each sample.
You should consider your load in reference to the number of CPU's you
have in a system. If you have 8 CPU's, then having a load of 7 isn't a
problem. If the load is higher than the number of CPU's then you should
look at your top's CPU stats, and look at iostat and vmstat and sar.
A box can have a high load for several different reasons (or
combinations of those reasons). You may have a number of processes all
running simultaneously and the CPU is just running as fast as possible
(evidenced by less than 2% idle time shown in top for CPU usage).
You may have a number of processes that are in run states, but are
waiting for data i/o (evidenced by having abundant CPU idle time, but
still having a load higher than the number of CPU's).
Check vmstat for memory swap activity, i/o activity
-Ben.
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