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add cache warm-up for the first page access

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This commit is contained in:
Stefan Lankes 2016-05-03 16:56:49 +02:00
parent f0eb7c327a
commit 95f51da71f
1 changed files with 28 additions and 7 deletions
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35
hermit/usr/benchmarks/basic.c
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@ -57,17 +57,29 @@ void reschedule(void);
#endif
#define N 10000
#define M (1024)
#define M (1024+1)
#define BUFFSZ (1ULL*1024ULL*1024ULL)
static char* buff[M];
#if 0
inline static unsigned long long rdtsc(void)
{
unsigned long lo, hi;
asm volatile ("rdtsc" : "=a"(lo), "=d"(hi) :: "memory");
return ((unsigned long long) hi << 32ULL | (unsigned long long) lo);
}
#else
inline static unsigned long long rdtsc(void)
{
unsigned int lo, hi;
unsigned int id;
asm volatile ("rdtscp" : "=a"(lo), "=c"(id), "=d"(hi) :: "memory");
return ((unsigned long long)hi << 32ULL | (unsigned long long)lo);
}
#endif
int main(int argc, char** argv)
{
@ -78,8 +90,10 @@ int main(int argc, char** argv)
printf("Determine systems performance\n\n");
// cache warm-up
ret = mygetpid();
ret = mygetpid();
start = rdtsc();
for(i=0; i<N; i++)
ret = mygetpid();
@ -87,8 +101,10 @@ int main(int argc, char** argv)
printf("Average time for getpid: %lld cycles, pid %ld\n", (end - start) / N, ret);
// cache warm-up
reschedule();
reschedule();
start = rdtsc();
for(i=0; i<N; i++)
reschedule();
@ -96,22 +112,27 @@ int main(int argc, char** argv)
printf("Average time for sched_yield: %lld cycles\n", (end - start) / N);
malloc(1);
malloc(1);
// cache warm-up
buff[0] = (char*) malloc(BUFFSZ);
start = rdtsc();
for(i=0; i<M; i++)
for(i=1; i<M; i++)
buff[i] = (char*) malloc(BUFFSZ);
end = rdtsc();
printf("Average time for malloc: %lld cycles\n", (end - start) / M);
printf("Average time for malloc: %lld cycles\n", (end - start) / (M-1));
// cache warm-up
for(j=0; j<BUFFSZ; j+=4096)
buff[0][j] = '1';
start = rdtsc();
for(i=0; i<M; i++)
for(i=1; i<M; i++)
for(j=0; j<BUFFSZ; j+=4096)
buff[i][j] = '1';
end = rdtsc();
printf("Average time for the first page access: %lld cycles\n", (end - start) / (M*BUFFSZ/4096));
printf("Average time for the first page access: %lld cycles\n", (end - start) / ((M-1)*BUFFSZ/4096));
#if 0
write(2, (const void *)str, len);