On 8-mrt-2006, at 23:11, Brian Hurt wrote:

> Love to.  Wanna buy me the box?  :-}  Seriously- my code is  
> attached, if someone wants to run it on other boxes and post the  
> results, feel free. It's GNU-C/x86 specific, as I'm using GNU C's  
> inline assembler and the rdtsc instruction to get accurate cycle  
> counts.

I don't know if rdtsc is accurate on 64bit, but this is what running  
it on a dual opteron 250 running 64bit linux gives:

$ ./lock
Minimum time for a rdtsc instruction (in clocks): 144099185
Minimum time for a mutex lock+unlock + rdtsc (in clocks): 24

multiple runs hover between this and 37 clocks for the mutex, and  
more than twice for the rdtsc.

Lodewijk