Understanding Load Average, ‘top’ CommandPosted: February 20, 2011
Load Average is caused by two things
1. Cpu it self is busy/overloaded in processing things
2. Processes (typically called Blocking process) in run queue, waiting for I/O
Andy Miller nicely explained with screen shots to find what cause the high load average.
Here is Screen shot from ‘Top’ command
If the first two figures %us and %sy are near to 90% then Cpu is overloaded and needs to be upgrade.
If the 5th figure in same line %wa is shows high numbers means there are some jobs in run queue waiting for I/O (may be trying to read data from mounting disk). Then look for that.
To diagnose which process causing this just run a command
and look ‘D’ under 8th column STAT one. There may be lots of R and S as well.
D —> Waiting for either (CPU, Disk I/O, Network I/O)
R —-> Running
S —–> Sleeping
I use the command
ps axo stat,pid | grep D
to find the process with stat D
Here is link where i learned all that
Thanks to Mr. Andy Millar.
No more fear of ‘top’ Command.Have fun!