用VTune进行性能调优

#include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <time.h> #include <netinet/ip6.h> #include <immintrin.h> #ifndef likely #define likely(x) __builtin_expect(!!(x), 1) #endif #ifndef unlikely #define unlikely(x) __builtin_expect(!!(x), 0) #endif static inline uint64_t rte_rdtsc(void) { union { uint64_t tsc_64; struct { uint32_t lo_32; uint32_t hi_32; }; } tsc; _mm_mfence(); asm volatile("rdtsc" : "=a" (tsc.lo_32), "=d" (tsc.hi_32)); return tsc.tsc_64; } #define ARRAY_LEN 2048 #define LOOP_CNT 1000 int array[ARRAY_LEN][ARRAY_LEN]; int cachetest2() { int i = 0; int j = 0; int nBlockWidth = 128 / sizeof(int) * 8; int nBlocks = ARRAY_LEN / nBlockWidth; int nRemain = ARRAY_LEN % nBlockWidth; int sum_total = 0; __m128i sum = _mm_setzero_si128(); __m128i load; /* set array */ for (i = 0; i < ARRAY_LEN; i++) { for (j = 0; j < ARRAY_LEN; j++) { array[i][j] = rand() % 1024; } } for (i = 0; i < ARRAY_LEN; i++) { const __m128i *p = (const __m128i *)array[i]; for (j = 0; j < nBlocks; j++) { load = _mm_load_si128(p); sum = _mm_add_epi32(sum, load); p++; } const int *q = (const int *)&sum; sum_total += (q[0] + q[1] + q[2] + q[3]); if (unlikely(nRemain)) { for (j = 0; j < nRemain; j++) { sum_total += q[j]; } } } return sum_total; } int cachetest() { int i = 0; int j = 0; int sum = 0; for (i = 0; i < ARRAY_LEN; i++) { for (j = 0; j < ARRAY_LEN; j++) { array[i][j] = rand() % 1024; } } for (i = 0; i < ARRAY_LEN; i++) { for (j = 0; j < ARRAY_LEN; j++) { //sum += array[i][j]; sum += array[j][i]; } } return sum; } int main(void) { uint64_t start, end; int i = 0; srand((unsigned)time(NULL)); start = rte_rdtsc(); for (i = 0; i < LOOP_CNT; i++) { cachetest(); } end = rte_rdtsc(); printf("calc time: %ld\n", end - start); return 0; }