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switch back to rdtsc

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- no all emulators supports rdtscp
This commit is contained in:
Stefan Lankes 2015-08-28 23:07:03 +02:00
parent f520c0ca56
commit 84deb1a261
1 changed files with 12 additions and 14 deletions
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26
hermit/usr/examples/jacobi.c
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@ -40,12 +40,18 @@
#define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))
extern unsigned int get_cpufreq();
static unsigned long long start_tsc;
inline static unsigned long long rdtscp(void)
inline static unsigned long long rdtsc(void)
{
unsigned long long lo, hi;
asm volatile ("rdtscp; lfence" : "=a"(lo), "=d"(hi) :: "%rcx", "memory");
return (hi << 32 | lo);
unsigned long lo, hi;
asm volatile ("rdtsc; mfence" : "=a"(lo), "=d"(hi) :: "memory");
return ((unsigned long long) hi << 32ULL | (unsigned long long) lo);
}
__attribute__((constructor)) static void timer_init()
{
start_tsc = rdtsc();
}
double mysecond()
@ -58,18 +64,10 @@ double mysecond()
i = gettimeofday(&tp,&tzp);
return ( (double) tp.tv_sec + (double) tp.tv_usec * 1.e-6 );
#else
static unsigned long long start;
static int init = 0;
double ret;
if (init) {
ret = (double) (rdtscp() - start) / ((double) get_cpufreq() * 1000000.0);
} else {
//printf("CPU frequency: %d MHz\n", get_cpufreq());
start = rdtscp();
init = 1;
ret = 0.0;
}
ret = (double) (rdtsc() - start_tsc) / ((double) get_cpufreq() * 1000000.0);
//printf("CPU frequency: %d MHz\n", get_cpufreq());
return ret;
#endif