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68 lines
2.8 KiB
C
68 lines
2.8 KiB
C
/* COPYING:
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* Dave Patterson at UCB modified this code from a program by Andrea
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* Dusseau of U.C. Berkeley,which was based on a description in
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* Saavedra-Barrera [1992]:
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* Saavedra-Barrera, R. H. [1992]. CPU Performance Evaluation and
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* Execution Time Prediction Using Narrow Spectrum Benchmarking,
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* Ph.D. Dissertation, University of Calif., Berkeley (May).
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* Patterson has given permission to use and modify this code as long
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* as these people and the U. of Cal., Berkeley get proper credit.
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*/
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#include <stdio.h>
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#include <sys/times.h>
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#include <sys/types.h>
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#include <time.h>
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#define CACHE_MIN (1024) /* smallest cache */
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#define CACHE_MAX (256*1024) /* largest cache */
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#define SAMPLE 10 /* to get a larger time sample */
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#ifndef CLK_TCK
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#define CLK_TCK 60 /* number clock ticks per second */
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#endif
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int x[CACHE_MAX]; /* array going to stride through */
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double get_seconds() { /* routine to read time */
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struct tms rusage;
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times(&rusage); /* UNIX utility: time in clock ticks */
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return (double) (rusage.tms_utime)/CLK_TCK;
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}
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int main() {
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int register i, index, stride, limit, temp;
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int steps, tsteps, csize;
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double sec0, sec; /* timing variables */
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for (csize=CACHE_MIN; csize <= CACHE_MAX; csize=csize*2)
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for (stride=1; stride <= 128; stride=stride*2) {
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sec = 0; /* initialize timer */
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limit = csize-stride+1; /* cache size this loop */
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steps = 0;
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do { /* repeat until collect 1 second */
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sec0 = get_seconds(); /* start timer */
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for (i=SAMPLE*stride;i!=0;i=i-1) /* larger sample */
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for (index=0; index < limit; index=index+stride)
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x[index] = x[index] + 1; /* cache access */
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steps = steps + 1; /* count while loop iterations */
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sec = sec + (get_seconds() - sec0);/* end timer */
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} while (sec < 1.0); /* until collect 1 second */
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/* Repeat empty loop to loop subtract overhead */
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tsteps = 0; /* used to match no. while iterations */
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do { /* repeat until same no. iterations as above */
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sec0 = get_seconds(); /* start timer */
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for (i=SAMPLE*stride;i!=0;i=i-1) /* larger sample */
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for (index=0; index < limit; index=index+stride)
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temp = temp + index; /* dummy code */
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tsteps = tsteps + 1; /* count while iterations */
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sec = sec - (get_seconds() - sec0);/* - overhead */
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} while (tsteps<steps); /* until = no. iterations */
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printf("Size (bytes):%7d, Stride (bytes):%4d, read+write:%4.0f
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ns\n",
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csize*sizeof(int), stride*sizeof(int),
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(double) sec*1e9/(steps*SAMPLE*stride*((limit-1)/stride+1)));
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}; /* end of both outer for loops */
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}
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