What is the maximum value of 'load' ?

[TBOSS]

I am very curious with 'load' value.

What is the maximum possible value of 'load', i.e. from 'top' utility ?

And what does it come from, how it is being calculated ?

[randy lee]

The load value is jobs waiting to run or runq.
It should be 1 or less. If it is more than that most of the time, the system is cpu bound, and you will probably need to add cpus.

[Paul Hite]

The load is the number of processes that are in one of 3 states:
1) running...literally in a cpu
2) ready to run now...they want a cpu asap
3) waiting for disk i/o to complete...they will want a cpu very soon (in theory)

So the max, I guess, is NPROC, which is the size of the process table. But it would be hard to fill the process table completely with processes in one of the 3 above states.

[John_Hancock]

This is an excelent question. How long is a peice of string.

I have seen a runq of 1 where the host is obviously over worked and I have seen a runq of 72 (yes 72 - no typo) where the host was performing perfectly.

We are running ITO on a host which spends much of its time around four and peaks at about 12. This is bad. This host is sluggish and performs badly. There was one case where the runq steadily increased from about 1.5 to 7 over a six month period. When it got to 7 processes began to core. In a panick the sys admin doubled the processors and doubled the ram (taken from the standby host) and the runq dropped to about two where its performance was once again acceptable.

In answer to your origonal question - there is no right answer. The keys questions are - Do your processes run as expected? and Is the host performance acceptable? If the answer is yes then you have nothing to worry about.

John Hancock

[TBOSS]

I have problem running some applications on multi CPU machines. They are really slow...

First application (database), I checked 'load' and see value less than 0.3. And could not determine the cause of problem. May have to check waiting I/O, but the previous questions say something that applications that wait for I/O should be account to 'load' value too...

Second application (database + script) , 'load' says 6-7 and sometimes 10.

I am curious with the value of 'load'. (In past, I thought it will not go beyond 1) What is it come from, what is the unit (i.e. seconds) and what is the maximum value of it ?

[Dave Wherry]

As John said, a high value may not mean there is a problem. Many of the newer, faster processors will have a higher load value and be able to handle it.
As for your database system with a low value, but, sluggish performance, that load value is not showing the whole picture. There is likely a couple of processes that are you database engine. These may be multi-threaded, a whole bunch of users using each process, that Unix or load value is not going to see into. You need to use other tools to drill down.
Don't get too hung up on load value. Don't discard it either. You just need to look deeper.