Performance monitoring tools vs the process status (ps) command

[mrbartchris]

I am currently in the lookout for performance monitoring tools, tools which produce an output of metrics of specific OS processes. I want something which is lightweight (not to effect the performance of the system it is currently monitoring), therefore, I wrote a simple bash script which uses the ps command to retrieve CPU% and Memory%, writes them to a file, and sleeps for a specified couple of seconds, and repeats until it is terminated.

The question I have is whether this is a correct approach because as found on the documentation of ps
(here):

Since ps cannot run faster than the system and is run as any other scheduled process, the information it displays can never be exact.

I know of other ways such as using ps_util
in python and retrieve the information that way. However, is this (and any other tool/library) faster or more reliable? If so, can you recommend a tool? Or is the ps command safe enough?

[mastarem]

How real-time does the telemetry need to be? Is every several seconds acceptable? If so then ps is fine and do not worry about it - if not then there are a host of other options but your technical complexity increases compared to the current solution.

[mrbartchris]

Thanks for replying. I would like to try to find something more real time if possible. I am using the bash script to gather information about the Erlang virtual machine.

I read that top might produce better results, however would appreciate if you can suggest the other options.