Infrastructure Software

I'm trying to get percentage CU over a larger period.

Here is what I get using the elapse time and cpu time formula.


(The format is pid, % CPU, virtual mem, mem, cpu time, elapsed time, args to the process)


ps -efo pid,pcpu,vsz,rss,time,etime,args | grep mypro

7620 18.3 361976 345400 07:37:45 12:25:23 mypro

(wait for some time)

ps -efo pid,pcpu,vsz,rss,time,etime,args | grep mypro

7620 18.2 361976 345400 07:37:50 12:25:30 mypro



The delta for elapsed time is 12:25:30 - 12:25:23 = 7 sec

The delta for CPU time is 07:37:50 - 07:37:45 = 5 sec.



The percentage CPU is 100*5/7 = 71 %



This appears to be 4x the number of CPUs.


I�m not finding any google to confirm this. Any help would be great!.


My problems are:
1. The figures given by pcpu (18.2 or 18.3%) doesn't match with the above calculation (71%) I would like to know if my formula is good :|

2. If the above formula has to do with the number of CPUs, can I get that within the ps command itself?

thanks,
-Vikrantl