Unix™ Systems Programming [Electronic resources] : Communication, Concurrency, and Threads نسخه متنی

22.9 Process-worker Pool

Implement a process-worker pool, whereby each worker process blocks on accept. The server takes two command-line arguments: the listening port number and the number of worker processes to fork.

Compare connection times for the process-worker pool with those for the thread pool of Section 22.7. Explore performance as a function of offered load. Explore hybrid designs in which a pool of threaded process workers blocks on accept. Each threaded process maintains a pool of worker threads as in Section 22.7.

Exercise 22.14

How would you determine whether the backlog value set by listen affects server performance?

Answer:

The backlog is set in UICI to the value of the MAXBACKLOG constant defined near the top of uici.c in Program C.2. Pick parameters that put a moderate load on the server and recompile with different values of the backlog. UICI uses the default value of 50 if MAXBACKLOG is not defined. You can use the -D option on the compile line to define MAXBACKLOG. Start with this value and then modify it and see if smaller or larger values affect the performance of the server.