Summery: CPU load Average.

From: Jassim (
Date: Mon Aug 21 2000 - 00:15:23 CDT

I'd like to thank the following:

James R Grinter
Matthew Stier
Bill Armand
Stephen Harris
Scott Howard

Will it turns out that the machine will never reboot just because the CPU load is high. It will keep on working but with poor performance.

following are some of the answers I recieved:

There is no such limit.

A machine should never panic due to high load.



The system will never panic and reboot simply due to a high load average.

A high load average is not necessarily bad either - it's just one of many
things to look at if you think you have performance issues. eg I had a
single CPU ss20 with a load average of over 100 and it worked OK...



I've worked with Sun equipment since there has been Sun equipment and I don't know of any CPU load that would cause a panic reboot. What is experienced is slowness in response of the system. The higher the CPU utilization goes the system will seem slower and slower and eventually seem to stop completely.... but NOT reboot. To the user it will appear to have stopped when CPU utilization reaches 100%... but the system will continue to work the processes in order until it catches up. This is not a good situation because the perception of your users will be that the system is slow, not responsive... etc, etc.

Panics and then reboots are generally caused by either faulty code or equipment.



Simple answer: None.
The CPU load number is simply the number of jobs waiting for a cpu. The optimum is 1 per cpu.

If the load level is under 1 per cpu, it simply means that there isn't enough work to keep the cpu(s) busy.

If the load level is over 1 per cpu, it simply means that there is more work than the cpu(s) can handle, and application performance may decrease.

There is no "magic number" when the system will just panic and reboot.


----- Original Message -----
From: Jassim
Sent: Saturday, August 19, 2000 11:10 AM
Subject: CPU load Average.

Dear Sun Managers,

I have this simple yet important question (to me) ,, My question is :

what is the CPU load average number that when reached the system will panic and reboot?

I have an old SparcServer20 with 2*75MHZ CPU's ,, this machine is used as an internal webserver for one of our departments. I'm monitoring it using Big Brother ,,, which repeativly reports that the server has high CPU load average.

will summerize.

Thanking you guy's in advance.

Jassim Seyadi

U BEFORE POSTING please READ the FAQ located at
. and the list POLICY statement located at
A To submit questions/summaries to this list send your email message to:
A To unsubscribe from this list please send an email message to:
E and in the BODY type:
R unsubscribe sun-managers
S Or
. unsubscribe sun-managers original@subscription.address
L To view an archive of this list please visit:

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:14:15 CDT