What is a "fork" reported by nMon

From: Jn (jnethercutt_at_wehco.com)
Date: 12/23/03 

Date: 23 Dec 2003 14:43:47 -0800

I'm trying to use nMon for performance monitoring and analysis. I
read somewhere that a value of more than 3 forks per second is a bad
thing. I'm looking at the nMon analyzer results - the tab labeled
"PROC". The "fork" column has many instances greater than 3. Here is
a snapshot from one days statistics sorted descending on "fork":

Processes RunnableSwap-in pswitch syscall read write fork exec
15:20:04 2.44 1.1 7989 23556 3845 22 17 17
14:00:04 1 1 317 6522 539 28 14 26
15:19:34 1.4 1.07 5476 17576 2590 14 11 10
15:07:04 1.79 1.03 1641 4720 572 25 10 10
14:15:04 1.57 1.13 8256 15166 2765 33 9 7
15:08:04 1.82 1 1191 3903 429 16 9 9
15:39:04 1.94 1.03 8383 21948 3411 19 9 9
15:54:35 1.29 1 226 2253 258 17 9 9
15:55:35 2.71 1 1228 8052 374 42 9 9
15:27:04 2.1 1.13 14027 27325 4634 14 8 6
15:34:34 2.15 1.03 15353 35186 5154 89 8 8
15:03:04 2.33 1.03 9044 22441 2912 13 7 6
15:03:34 1.84 1 4649 7210 182 13 7 6
15:04:34 1.96 1 5002 11031 432 13 7 6
15:05:04 2.22 1.03 13934 29957 4504 21 7 6
15:08:34 2.17 1 880 3078 407 16 7 6
15:16:04 1.72 1.03 2635 4309 152 9 7 6
15:18:34 1.58 1.07 1113 6554 670 24 7 7
15:20:34 1.8 1 1108 4026 418 9 7 6
15:22:04 1.41 1 10440 20003 3242 11 7 6
15:35:34 1.67 1.1 387 2675 208 26 7 6
15:36:04 1.67 1.03 521 2659 220 52 7 6
15:06:34 2 1.03 2380 7203 495 25 6 6
15:15:34 1.11 1 920 2821 223 15 6 6
  
First of all, in terms of AIX processor performance, what exactly is a
"fork"? Then, should I take measures to reduce the number of forks
that occur on the system? If so, please suggest specific measures -
more memory, more cpu's, parameter tuning?

This is AIX 4.3.3, 3GB RAM, 2 CPUs, Informix 9.31.

Thank you,
jn