Help Measuring Fork/Exec Overhead

[JuhlinB]

I am trying to determine the cost/overhead involved in a fork/exec sequence
under Unix 5.2 on a 3B5 (I'll probably do other AT&T machines after this).

I've managed to track through the code and predict the overhead of an exec
given the process's size.  My measurements (particularly the I/O's) are 
very consistent with what I predict.

Unfortunately, tracking/predicting fork overhead seems much more difficult.
CPU usage seems to be marginally affected by process size and much more
affected by the number of processes in the proc table.

Are there other factors I should be aware of in determining fork overhead?

Any good ideas on how to measure it? 

[I'm currently getting the CPU time for a parent that fork's a child and
waits for its completion.  The parent does this 100 times.
I've done this for parents of varying sizes, and with the system in
run-states 1, 2, 3 (5, 18, and 71 processes in the table, respectively).]

Do you know of any memos, etc. that have addressed this issue?

Any comments, suggestions, or guidance you can give will be greatly
appreciated.  Feel free to contact me via the net or mail.

Thanks,

Bruce Juhlin
druak!juhlin