Solved

In 'uptime' output, what does "load average" mean, and when does the number become "bad"?

Posted on 2004-04-07
4
13,928 Views
Last Modified: 2011-10-03
According to the AIX man page for the 'uptime' command, the following is true:

"The uptime command prints the current time, the length of time the system has been up, the number of users online, and the load average. The load average is the number of runnable processes over the preceding 5-, 10-, 15-minute intervals."

My numbers are usually below one, so I haven't been concerned.  Lately, the numbers are sometimes getting higher.

Can you tell me what the "load average" or "runnable processes" means, and at what point the number becomes "bad"?

In other words, is 1.5 okay, but 5.3 bad?  The man page is not very informative on this issue.

Thank you!!

Unca Xitron
0
Comment
Question by:Xitron
4 Comments
 
LVL 48

Accepted Solution

by:
Tintin earned 125 total points
ID: 10779306
The load average is the average number of processes in the run queue.  By that, it means the number of processes waiting to be processed by the CPU.  The uptime command gives you a 5,10 and 15 minute average so that you can see if the server performance  is getting worse/better/stable.

As to what a good and bad figure is, depends a bit on the system and type of processes running.  As a very rough rule of thumb, when the load average gets above 10, you may experience some minor performance issues.  However, I've been on some systems where we've had the load average over 500 and the system coped OK (obviously not as efficient as when it is in normal operation).

Load average is just one component at looking at general performance.  You really need to look at it in conjunction with memory and I/O to get an overall view.
0
 
LVL 45

Assisted Solution

by:sunnycoder
sunnycoder earned 125 total points
ID: 10781025
>Can you tell me what the "load average" or "runnable processes" means, and at what point the
>number becomes "bad"?
There are 5 main stages in the lifetime of a process
1. Entry .... when it is just invoked
2. running ... when it has a CPU and is running
3. runnable ... when it is ready to run and is waiting for a CPU
4. waiting .... when it is blocked waiting for something such as I/O or semaphore
5. exited/stopped

from OS point of view, we often consider 2+3 together as runnable and divide 5 to incorporate zombies ...

So for your question a runnable process is any process which is ready to execute ... it may or may not have CPU at the current moment ....

OS maintains a queue of the runnable processes ... Whenever currently executing task has completed or it needs to be rescheduled or blocked, OS just picks a process from the runqueue and starts executing it ....

So load average would mean that over last n minutes, at an average, how many tasks were in the runqueue ....

I hope it makes some sense
0
 
LVL 61

Expert Comment

by:gheist
ID: 10782987
Depends on how you tune system (task scheduler, swap management, disk buffers, mealloc() )
Install and patch bos.adt.samples package from 1st CD, so you get vmtune utiliy to tune malloc parameters, especially swap threshold can be multiple megabytes instead of default one, and read the README as dmesg said, to tune individual applications.
Check out "smitty wlm" , it has very simple interface and helps you group and prioritize applications as necessary ( first try monitoring mode to see how well you grouped your processes )
e.g.
Kernel min=20% max=100% cpu and memory (root is included here, do not lower that 20%)
Interactive logins (gid=users) -"-
Database application (uid=postmaster) -"-
Webserver (program=/usr/IBMHTTPServer/bin/httpd)-"-
default -"-
i.e. you do not know how much resource each one needs, so give them equal share of resources, so they all run at once without bringing others down, then you will gain experience who needs a bit more or less and adjust settings accordingly.
I run 12 workload classes on one test server, this becomes less on actual business servers
0
 

Author Comment

by:Xitron
ID: 10784069
My thanks to all for your excellent information!

Unca Xitron
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Hello fellow BSD lovers, I've created a patch process for patching openjdk6 for BSD (FreeBSD specifically), although I tried to keep all BSD versions in mind when creating my patch. Welcome to OpenJDK6 on BSD First let me start with a little …
Let's say you need to move the data of a file system from one partition to another. This generally involves dismounting the file system, backing it up to tapes, and restoring it to a new partition. You may also copy the file system from one place to…
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…
In a previous video, we went over how to export a DynamoDB table into Amazon S3.  In this video, we show how to load the export from S3 into a DynamoDB table.

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

22 Experts available now in Live!

Get 1:1 Help Now