I don't think it's filesystem related, i.e. there is not much I/O happening at
the time. Maybe NetBSD's /bin/sh is a lot faster than Solaris
/bin/{sh,ksh,bash}, maybe NetBSD's fork() is a lot faster. I didn't benchmark
the two operating systems. I'm hoping to conduct some benchmarks soon and will
post the results.
This brings me to another question: newer x86 CPUs have a time stamp counter,
wich can be accessed with rdtsc assembly instruction. I think ultrasparc CPUs
have a similar counter, accessed via %tick register. This is useful in
benchmarks when measuring high resolution timing evens.
On x86 with GCC I use the following function to take a time stamp:
uint64_t rdtsc(void) {
/*
** rdtsc sets register %edx to the high-order 32 bits of the counter
** and register %eax to the low-order 32 bits. Those values are stored
** in an array of two 32 bit integers, and returned as a single 64 bit
** value.
*/
union {
uint64_t u64ts;
uint32_t u32arr[2];
} un_rdtsc;
__asm__ __volatile__ ("rdtsc; movl %%edx,%0; movl %%eax,%1"
: "=r" (un_rdtsc.u32arr[1]), "=r" (un_rdtsc.u32arr[0])
: /* No input */
: "%edx", "%eax");
return(un_rdtsc.u64ts);
}
The above function will work with GCC, but I think it will not compile with
SunPro compiler. Does anyone have any suggestions on how I could convert such a
function into portable x86 and sparc assembly code (using rdtsc for x86 and
%tick for sparc)?
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