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> Does anyone know what the response time for gettimeofday() is on a
> reasonably modern Pentium?  It is about 60 microseconds on my ancient 386. 

I wrote some test code for this, included below.

My results (as measured by this code)

Machine                Calls                   Latency

PPro-180               999998                  4.06us
Nexgen P-100           999977                  23.92us
Pentium-100            999987                  4.81us
Cyrix-PR166            999996                  5.82us

I guess that kinda says something bad about that NexGen machine I used to
test the AIOX driver, mainly that it is slow, which for testing I guess is
kinda good. Maybye it is just slower in the call gate or something because
computational I think it is a bit faster than the Pentium 100 (at least
that is my experience with the equally equipped machines).

------------------------ The Code -------------------------------------

#include <sys/time.h>
#include <stdio.h>
#define TESTLEN 1000000

void main (void)
{
  struct timeval a,b;
  long d;
  long t = 0;
  int x, c= 0;

  for (x=0;x<TESTLEN;x++)
  {
     gettimeofday (&a, NULL);
     gettimeofday (&b, NULL);

     if ((a.tv_sec == b.tv_sec) && (d = b.tv_usec - a.tv_usec))
      { c++; t += d;}
      
  }
  
  printf ("Summary %d gettimeofday() pair calls, mean latency = %0.2fus\n",
           c,  (float)t / c); 

}