57 lines
1.5 KiB
C
57 lines
1.5 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#define SAMPLES 100000
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#define CACHE_LINE 64
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int time_access_no_flush(const char *adrs) {
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volatile unsigned long time;
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asm __volatile__ (
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" mfence \n"
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" lfence \n"
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" rdtsc \n"
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" lfence \n"
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" movl %%eax, %%esi \n"
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" movl (%1), %%eax \n"
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" lfence \n"
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" rdtsc \n"
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" subl %%esi, %%eax \n"
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: "=a" (time)
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: "c" (adrs)
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: "%esi", "%edx");
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return time;
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}
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void flush(const char *adrs) {
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asm __volatile__ ("mfence\nclflush 0(%0)" : : "r" (adrs) :);
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}
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const char x[] = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\x00"
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"BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\x00"
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"CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC\x00"
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"DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD\x00";
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int main (int argc, char **argv)
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{
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unsigned int *times = malloc(SAMPLES * sizeof(unsigned int));
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if (times == NULL) {
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return 1;
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}
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int i;
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for (i = 0; i < SAMPLES; i++) {
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// Flush the first time, and then every second time.
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// So that it's uncached, cached, uncached, cached, ...
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if (i % 2 == 0) {
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flush(x);
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}
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times[i] = time_access_no_flush(x);
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}
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for (i = 0; i < SAMPLES; i++) {
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printf("%u\n", times[i]);
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}
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return 0;
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}
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