53 lines
1.3 KiB
C++
53 lines
1.3 KiB
C++
#include <iostream>
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#include <sys/time.h>
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#include <random>
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using namespace std;
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const int SIZE = 256 * 1024 * 1024;
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const int pagenum = 16 * 1024;
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const int pagesize = SIZE / pagenum;
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void xorsum_seq(int *data)
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{
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int xorsum = 0;
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timeval start, end;
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gettimeofday(&start, nullptr);
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for (int page = 0; page < pagenum; page++)
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{
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for (int idx = 0; idx < pagesize; idx++)
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xorsum ^= data[page * pagesize + idx];
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}
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gettimeofday(&end, nullptr);
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double usec = (end.tv_sec - start.tv_sec) + (double)(end.tv_usec - start.tv_usec) / 1000000;
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cout << __func__ << " duration: " << usec << ", xorsum: " << xorsum << endl;
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}
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void xorsum_jmp(int *data)
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{
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int xorsum = 0;
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timeval start, end;
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gettimeofday(&start, nullptr);
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for (int idx = 0; idx < pagesize; idx++)
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{
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for (int page = 0; page < pagenum; page++)
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xorsum ^= data[page * pagesize + idx];
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}
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gettimeofday(&end, nullptr);
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double usec = (end.tv_sec - start.tv_sec) + (double)(end.tv_usec - start.tv_usec) / 1000000;
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cout << __func__ << " duration: " << usec << ", xorsum: " << xorsum << endl;
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}
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int main()
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{
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int *data = new int[SIZE];
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int xorsum = 0;
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srand(time(nullptr));
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for (int idx = 0; idx < SIZE; idx++)
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{
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data[idx] = rand();
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}
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xorsum_seq(data);
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xorsum_jmp(data);
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} |