Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site druak.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!mtuxo!drutx!druak!juhlin From: juhlin@druak.UUCP (JuhlinB) Newsgroups: net.unix,net.unix-wizards Subject: Help Measuring Fork/Exec Overhead Message-ID: <782@druak.UUCP> Date: Tue, 20-Aug-85 19:33:29 EDT Article-I.D.: druak.782 Posted: Tue Aug 20 19:33:29 1985 Date-Received: Sat, 24-Aug-85 01:24:34 EDT Organization: AT&T Information Systems Laboratories, Denver Lines: 31 Xref: watmath net.unix:5425 net.unix-wizards:14474 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