How to find the maximum CPU memory used by a process

[ZQH at psuvm.psu.edu]

As you know, the RISC Unix workstations becomes more and more affordable
and powerful.  As a result, more and more people move their engineering
applications from mainframes (like CRAY-YMPs & IBM3090s) to those
powerful workstations.  As some of you may have noticed, one of the
major differences between mainframes and workstations is, on the
workstation, the available CPU memory is much less than the one
on the mainframe.  So it is important to know & control the CPU
memory, especially the maximum memory, your applications have used.

On the Unix system, there is a command "ps" for us to find some
informations about the CPU memory the processes are using (i.e.,
the INSTANTANEOUS memory at the given moment).  However, it is
the maximum CPU memory usage which determines if the specific
engineering application is able to run on certain workstations.

I understand there is a way to search for the maximum CPU usage
by using another background process to check "ps" periodically:

    #!/bin/sh
    #
    touch  ps.list
    #
    while  ps -ux | grep app.out > /dev/null
    do
      ps -ux | grep app.out >> ps.list
      sleep 10                       # whatever period you prefer
    done

By doing so, you may or may not find the maximum CPU memory usage
AND you have to look through tons of data for it.

I checked the man page for csh ("man csh") the other day and I found
something very interesting.  Under the section of "Enviromental
Variables and Predefined Shell Variables", there is something about
setting automatic timing threshold and timetags for various output,
one of them is the maximum CPU memory usage!  It's something like:

   set time = "1 '%U %S %E %P %M'"

However, I tried it several times without sucesses.
It only gave you the usual output from automatic timing
(in the man page, it says the default timetag format doesn't
including '%M', which displays the maximum CPU memory usage).
The default output is as followings:

   179.1856u 31.6673s 7:19 47%

I guess probably I didn't set something properly.

I think, in the NetWorld, there are a lot of Unix experts, who
are much more knowledgeable about the UNIX than I (I used to
use the IBM VM/CMS system and started learning Unix not long ago).

You may send the response via e-mail to me.  I'll try to post
a summary in the newsgroup 'comp.unix.questions'.

FYI, you can find the automatic timing under the section of
"Enviromental Variables and Predefined Shell Variable" in
the 'man csh' (near the end of it) and you have to be on
the AIX370 (e.g. AIX operating System with IBM3090).

If you need further information, please let me know.
Thanks a lot in advance.

                                    James

Name:  Zhijun James Huang
BITNet:  zqh at psuvm
Internet:  huang at prandtl.che.psu.edu
        or zqh at phoenix.psu.edu