Visit The New, Modern Unix Linux Community


Help with load average?


 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers Help with load average?
# 1  
Help with load average?

how load average is calculated and what exactly is it

difference between cpu% and load average
# 2  
I hope this is not homework.

Load averages are just that - load data gathered over a period of time, then averaged
ex.: disk busy % from iostat command, gathered once an hour
Code:
64%
35%
10%
average=$(( 64 + 35 + 10 ))
average=$((  $average / 3 ))
echo "hourly average = $average"

"load" can be defined as cpu utilization or disk utilization or memory utilization. Or all three. The primary concern about when load becomes an issue is when proccesses are forced to wait for the cpu, wait execessivly for I/O, wait for processes to swap in/out of memory.
# 3  
Technically, it is the number of blocking processes in the run queue averaged over a certain time period.

Using uptime as an example, the first number is the average over the last minute, the second number is the average over the last five minutes, and the third number is the average over the last 15 minutes.
# 4  
Quote:
Originally Posted by jim mcnamara
I hope this is not homework.

Load averages are just that - load data gathered over a period of time, then averaged
ex.: disk busy % from iostat command, gathered once an hour
Code:
64%
35%
10%
average=$(( 64 + 35 + 10 ))
average=$((  $average / 3 ))
echo "hourly average = $average"

"load" can be defined as cpu utilization or disk utilization or memory utilization. Or all three. The primary concern about when load becomes an issue is when proccesses are forced to wait for the cpu, wait execessivly for I/O, wait for processes to swap in/out of memory.
thankyou jim
so how to judge what value of load average is good for a system considering approximate value for system resources
# 5  
Depends what you want it to be. If your system is always busy, high is normal. Low is normal on a mostly idle system.

It's more useful for comparison. Sudden, unexpected changes can be indicative of problems. Low average on a system supposed to be busy -- did some daemon crash and die? High average on usually-idle system -- what's causing it?
# 6  
Quote:
Originally Posted by Corona688
Depends what you want it to be. If your system is always busy, high is normal. Low is normal on a mostly idle system.

It's more useful for comparison. Sudden, unexpected changes can be indicative of problems. Low average on a system supposed to be busy -- did some daemon crash and die? High average on usually-idle system -- what's causing it?
just for analysis, is there any theroy to calculate threshold value for any given machine
# 7  
threshold of what?

The raw value only tells you how busy it is, not how busy it should be. It's more useful for comparison. Sudden, unexpected changes can be indicative of problems.

Once it gets above 1 I'd call the machine very busy, and above 2 I'd call overloaded, but ymmv. You can tune a machine to work well even under high loads.

Last edited by Corona688; 09-26-2011 at 03:03 PM..
 

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

Test Your Knowledge in Computers #428
Difficulty: Medium
JavaScript supports regular expressions in a manner similar to Perl.
True or False?

10 More Discussions You Might Find Interesting

1. HP-UX

Load average unit

Hi, On load average graph, unit is 100m, 200m, 300...800m. I don't understand what it means. Thx for helping (3 Replies)
Discussion started by: Michenux
3 Replies

2. Solaris

Load Average and Lwps

NPROC USERNAME SWAP RSS MEMORY TIME CPU 320 oracle 23G 22G 69% 582:55:11 85% 47 root 148M 101M 0.3% 99:29:40 0.3% 53 rafmsdb 38M 60M 0.2% 0:46:17 0.1% 1 smmsp 1296K 5440K 0.0% 0:00:08 0.0% 7 daemon ... (2 Replies)
Discussion started by: snjksh
2 Replies

3. UNIX for Advanced & Expert Users

Load average in UNIX

Hi , I am using 48 CPU sunOS server at my work. The application has facility to check the current load average before starting a new process to control the load. Right now it is configured as 48. So it does mean that each CPU can take maximum one proces and no processe is waiting. ... (2 Replies)
Discussion started by: kumaran_5555
2 Replies

4. UNIX for Dummies Questions & Answers

Load Average threshold

What should be the threshold for load average of a quad core processor? What constitutes "good" and "bad" load average values? (2 Replies)
Discussion started by: proactiveaditya
2 Replies

5. UNIX for Dummies Questions & Answers

Please Help me in my load average

Hello AlL,.. I want from experts to help me as my load average is increased and i dont know where is the problem !! this is my top result : root@a4s # top top - 11:30:38 up 40 min, 1 user, load average: 3.06, 2.49, 4.66 Mem: 8168788k total, 2889596k used, 5279192k free, 47792k... (3 Replies)
Discussion started by: black-code
3 Replies

6. Solaris

load average query.

Hi, i have installed solaris 10 on t-5120 sparc enterprise. I am little surprised to see load average of 2 or around on this OS. when checked with ps command following process is using highest CPU. looks like it is running for long time and does not want to stop, but I do not know... (5 Replies)
Discussion started by: upengan78
5 Replies

7. UNIX for Dummies Questions & Answers

top - Load average

Hello, Here is the output of top command. My understanding here is, the load average 0.03 in last 1 min, 0.02 is in last 5 min, 0.00 is in last 15 min. By seeing this load average, When can we say that, the system load averge is too high? When can we say that, load average is medium/low??... (8 Replies)
Discussion started by: govindts
8 Replies

8. Shell Programming and Scripting

Determening load average.

Hi, I'm new to shell scripting. I need to make a script to add on to my cronjobs. The script must get the value of load average from my server and if its greater than 10 it should stop my apache service. I cant find a way to get the value of load average in integer type to do the check. Any... (4 Replies)
Discussion started by: jibsonline
4 Replies

9. UNIX for Dummies Questions & Answers

Load Average

Hello all, I have a question about load averages. I've read the man pages for the uptime and w command for two or three different flavors of Unix (Red Hat, Tru64, Solaris). All of them agree that in the output of the 2 aforementioned commands, you are given the load average for the box, but... (3 Replies)
Discussion started by: Heathe_Kyle
3 Replies

10. UNIX for Advanced & Expert Users

load average

we have an unix system which has load average normally about 20. but while i am running a particular unix batch which performs heavy operations on filesystem and database average load reduces to 15. how can we explain this situation? while running that batch idle cpu time is about %60-65... (0 Replies)
Discussion started by: gfhgfnhhn
0 Replies

Featured Tech Videos