hi, I'm profiling some part of kernel code.Mine profiling mechanism is based on rdtsc instruction.
Please tell me if i'm profiling correctly.I'm teting linux kernel 2.6.15 and mine system is P4. function(){ unsigned long long c1,c2,c3,c4,c5; before=readtsc(); before=readtsc(); before=readtsc(); overhead=readtsc()-before; c1=testfunc(); c2=testfunc(); c3=testfunc(); c4=testfunc(); c5=testfunc(); printk(" \n *c1 = %llu c2= %llu c3 = %llu c4 = %llu c5 = %llu overhead =%llu",cycles1,cycles2,cycles3,cycles4,cycles5,overhead); } /***************************************/ unsigned long long readtsc(){ unsigned long res[2]={0,0}; __asm__ __volatile__ ( "rdtsc\n" : "=a" (res[0]), "=d" (res[1]) ); return *((unsigned long long *)res); } /*******************************************/ unsigned long long testfunc(){ unsigned long start_cycles[2]={0,0}; unsigned long end_cycles[2]={0,0}; unsigned long long total_cycles=0; int i; __asm__ __volatile__ ( // read TSC, store edx:eax in res "rdtsc\n" : "=a" (start_cycles[0]), "=d" (start_cycles[1]) ); /* CODE TO BE PROFILED */ __asm__ __volatile__ ( // read TSC, store edx:eax in res "rdtsc\n" : "=a" (end_cycles[0]), "=d" (end_cycles[1]) ); total_cycles=*((unsigned long long *)end_cycles) - *((unsigned long long *)start_cycles); return total_cycles; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/