#include <bits/stdc++.h>
int main() {
    long l1 = sysconf(_SC_LEVEL1_DCACHE_SIZE);
    long l2 = sysconf(_SC_LEVEL2_CACHE_SIZE);
    long l3 = sysconf(_SC_LEVEL3_CACHE_SIZE);
    printf("L1 Cache = %ld B\n", l1);
    printf("L2 Cache = %ld B\n", l2);
    printf("L3 Cache = %ld B\n", l3);
    return 0;
}

在线 IDE 输出：

L1 Cache = 32768 B
L2 Cache = 1048576 B
L3 Cache = 34603008 B

因此，int 数据不超过 8192，long long 数据不超过 4096，是最快的