top and ps showing different results for cpu %

[Red Squirrel]

I noticed that top shows a different value for cpu use % as opposed to using ps. Has anyone ever noticed this, or am I maybe reading it wrong?

I wrote a simple php script that uses ps to display the resource usage of my VMs but then when I run top the results don't match at all. Thinking maybe my script was parsing wrong I typed ps and sure enough the results are different.

 

[Ken g6]

The ps man page says that, "CPU usage is currently expressed as the percentage of time spent running during the entire lifetime of the process. This is not ideal, and it does not conform to the standards that ps otherwise conforms to."

I didn't even know ps could display CPU usage %. I guess this is why nobody ever mentioned it.

 

[Red Squirrel]

Hmm that kind of sucks. Is there a way to get a top output in static format and sort it as well? (ex: a single command that returns to the promt)

 

[degibson]

Originally posted by: RedSquirrel
Hmm that kind of sucks. Is there a way to get a top output in static format and sort it as well? (ex: a single command that returns to the promt)

Depends on your platform. For me, its top -n 1
Try 'man top'

 

[n0cmonkey]

top -b -n 1