This is i386 machine-dependent part for Active Threads. It has been 
tested on the 200Mhz PentiumPro.

Here are the numbers in microseconds:


Pentium Pro, 200MHz
null call: 0.043
                                    Posix (Sun)     Active Threads
-------------------------------------------------------------------
thread create                          422                 2.1  
thread context switch                     		   0.7	 
context switch to self                                     0.25
uncontested mutex (lock/unlock)	       0.6                 0.45
uncontested semaphore (signal/wait)    2.8                 0.45
mutex ping-pong                       16.4		   3.0
semaphore ping-pong                   24.4                 3.0