I have to use rdtsc on ubuntu for performance evaluation. But i am not getting the correct value. I am placing a sleep on 10 seconds, but value i get is some 1 sec... i dont know where im going wrong?
Code:
#include<sys/time.h>
#include<time.h>
#include<stdio.h>
typedef unsigned long long ticks;
static __inline__ ticks getticks(void)
{
unsigned a, d;
asm("cpuid");
asm volatile("rdtsc" : "=a" (a), "=d" (d));
return (((ticks)a) | (((ticks)d) << 32));
}
int main(){
int r = 0;
ticks tick,tick1,tickh;
unsigned time =0;
tick = getticks();
sleep(10);
tick1 = getticks();
time = (unsigned)((tick1-tick)/1662543);
printf("\ntime in MS%u\n",time);
return 0;
}
cat /proc/cpuinfo gives
Code:
pprocessor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 14
model name : Genuine Intel(R) CPU T2300 @ 1.66GHz
stepping : 8
cpu MHz : 1662.543
cache size : 2048 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe constant_tsc up arch_perfmon bts pni monitor vmx est tm2 xtpr
bogomips : 3328.87
clflush size : 64
Last edited by vino; 09-18-2008 at 03:45 AM..
Reason: added code tags
