Drazen Urch
7bd1550195
* Checkpoint * cpu cycle ffi * Rename * mixnode feature * Bundle libcpucycles
94 lines
2.1 KiB
C
94 lines
2.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <time.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <cpucycles.h>
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#define TIMINGS 63
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static long long t[TIMINGS+1];
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static void t_print(void)
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{
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long long median = 0;
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long long i,j;
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for (i = 0;i < TIMINGS;++i)
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t[i] = t[i+1]-t[i];
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for (j = 0;j < TIMINGS;++j) {
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long long belowj = 0;
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long long abovej = 0;
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for (i = 0;i < TIMINGS;++i) if (t[i] < t[j]) ++belowj;
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for (i = 0;i < TIMINGS;++i) if (t[i] > t[j]) ++abovej;
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if (belowj*2 < TIMINGS && abovej*2 < TIMINGS) {
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median = t[j];
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break;
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}
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}
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printf(" %lld ",median);
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for (i = 0;i < TIMINGS;++i)
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printf("%+lld",t[i]-median);
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printf("\n");
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fflush(stdout);
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}
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static long long microseconds(void)
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{
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struct timeval t;
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long long result;
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gettimeofday(&t,(struct timezone *) 0);
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result = t.tv_sec;
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result *= 1000000;
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result += t.tv_usec;
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return result;
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}
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static volatile int v;
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static void measure_cpucycles(void)
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{
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long long loops,i,j;
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printf("cpucycles persecond %lld\n",cpucycles_persecond());
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printf("cpucycles implementation %s\n",cpucycles_implementation());
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for (i = 0;i <= TIMINGS;++i)
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t[i] = cpucycles();
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printf("cpucycles median"); t_print();
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for (loops = 1024;loops <= 1048576;loops *= 2) {
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long long t00,t01,t10,t11;
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long long m0,m1;
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double ratiobelow,ratioabove;
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t00 = cpucycles();
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m0 = microseconds();
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t01 = cpucycles();
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for (j = 0;j < loops;++j) v = 0;
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t10 = cpucycles();
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m1 = microseconds();
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t11 = cpucycles();
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if (t01 < t00) continue;
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if (t10 < t01) continue;
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if (t11 < t10) continue;
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if (m1 <= m0+2) continue;
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ratiobelow = floor((1000000.0*(t10-t01))/(m1+1-m0));
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ratioabove = ceil((1000000.0*(t11-t00))/(m1-m0-1));
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printf("cpucycles observed persecond %.0lf...%.0lf with %lld loops %lld microseconds\n",ratiobelow,ratioabove,loops,m1-m0);
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}
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}
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int main(int argc,char **argv)
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{
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cpucycles_tracesetup();
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printf("cpucycles version %s\n",cpucycles_version());
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measure_cpucycles();
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return 0;
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}
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