I've had occassion to provide CPU utilization feedback to the user. For instance, you might have a Tcl/Tk application that consumes lots of CPU cycles, but there are options which the user can implement to reduce the load. It's nice to provide direct feedback (without requiring the user to access a system utility).
Your application might also manage other applications, in which you might need to know how those applications are consuming resources.

Although I first titled this Wiki page for CPU utilization, the following can also be applied to measuring memory usage, uptime, etc.

'''Problem'''
How to determine CPU utilization for your running application.

'''Solution - UNIX'''
Use ''ps''. The Berkeley version of ''ps'' (Linux default, /usr/ucb/ps for Solaris) provides this bit of information, which can be retrieved rather easily via ''exec''. I'll use Solaris as my example, since that's what I'm most familiar with.

If you execute /usr/ucb/ps, you'll get two or more lines that look like this:
  USER       PID %CPU %MEM   SZ  RSS TT       S    START  TIME COMMAND
  mgbacke   5681  0.1  0.2 2440 1960 pts/6    S 10:31:36  0:0 /usr/bin/tcsh
More then likely, you'll get a lot of lines like this. What we really want is just the line associated with our application. To do this, give the ''ps'' command the ''u'' option, followed by the PID (Process ID) of the application:
  /usr/ucb/ps u 5681
which would return the output shown above.

To implement the above from within a Tcl application, you might implement a procedure such as this:
  proc getCPUutil { } {
      set result [exec /usr/ucb/ps u [pid]]
      set cpuUtil [lindex $result 13]
  }

You could also inline the code by doing everything on one line, but that's not by style:
  set CPU [lindex [exec /usr/ucb/ps u [pid]] 13]

''Marty Backe''
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HP, IBM, etc., users, please confirm a suitable version of ps is available.
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'''Solution - Windows'''
TBD - need help here.
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