Nevar pievienot vairāk kā 25 tēmas
Tēmai ir jāsākas ar burtu vai ciparu, tā var saturēt domu zīmes ('-') un var būt līdz 35 simboliem gara.
116 rindas
3.2 KiB
116 rindas
3.2 KiB
/* mountain.c - Generate the memory mountain. */
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/* $begin mountainmain */
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#include <stdlib.h>
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#include <stdio.h>
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#include "fcyc2.h" /* measurement routines */
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#include "clock.h" /* routines to access the cycle counter */
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#define MINBYTES (1 << 14) /* First working set size */
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#define MAXBYTES (1 << 27) /* Last working set size */
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#define MAXSTRIDE 15 /* Stride x8 bytes */
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#define MAXELEMS MAXBYTES/sizeof(long)
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/* $begin mountainfuns */
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long data[MAXELEMS]; /* The global array we'll be traversing */
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/* $end mountainfuns */
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/* $end mountainmain */
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void init_data(long *data, int n);
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int test(int elems, int stride);
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double run(int size, int stride, double Mhz);
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/* $begin mountainmain */
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int main()
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{
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int size; /* Working set size (in bytes) */
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int stride; /* Stride (in array elements) */
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double Mhz; /* Clock frequency */
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FILE *fp = NULL;
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fp = fopen("mountain.txt", "w+");
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init_data(data, MAXELEMS); /* Initialize each element in data */
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Mhz = mhz(0); /* Estimate the clock frequency */
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/* $end mountainmain */
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/* Not shown in the text */
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fprintf(fp, "Clock frequency is approx. %.1f MHz\n", Mhz);
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fprintf(fp, "Memory mountain (MB/sec)\n");
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fprintf(fp, "\t");
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for (stride = 1; stride <= MAXSTRIDE; stride++)
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fprintf(fp, "s%d\t", stride);
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fprintf(fp, "\n");
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/* $begin mountainmain */
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for (size = MAXBYTES; size >= MINBYTES; size >>= 1) {
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/* $end mountainmain */
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/* Not shown in the text */
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if (size > (1 << 20))
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fprintf(fp, "%dm\t", size / (1 << 20));
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else
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fprintf(fp, "%dk\t", size / 1024);
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/* $begin mountainmain */
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for (stride = 1; stride <= MAXSTRIDE; stride++) {
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fprintf(fp, "%.0f\t", run(size, stride, Mhz));
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}
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fprintf(fp, "\n");
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}
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fclose(fp);
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exit(0);
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}
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/* $end mountainmain */
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/* init_data - initializes the array */
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void init_data(long *data, int n)
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{
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int i;
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for (i = 0; i < n; i++)
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data[i] = i;
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}
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/* $begin mountainfuns */
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/* test - Iterate over first "elems" elements of array "data" with
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* stride of "stride", using 4x4 loop unrolling.
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*/
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int test(int elems, int stride)
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{
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long i, sx2 = stride*2, sx3 = stride*3, sx4 = stride*4;
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long acc0 = 0, acc1 = 0, acc2 = 0, acc3 = 0;
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long length = elems;
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long limit = length - sx4;
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/* Combine 4 elements at a time */
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for (i = 0; i < limit; i += sx4) {
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acc0 = acc0 + data[i];
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acc1 = acc1 + data[i+stride];
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acc2 = acc2 + data[i+sx2];
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acc3 = acc3 + data[i+sx3];
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}
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/* Finish any remaining elements */
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for (; i < length; i += stride) {
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acc0 = acc0 + data[i];
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}
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return ((acc0 + acc1) + (acc2 + acc3));
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}
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/* run - Run test(elems, stride) and return read throughput (MB/s).
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* "size" is in bytes, "stride" is in array elements, and Mhz is
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* CPU clock frequency in Mhz.
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*/
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double run(int size, int stride, double Mhz)
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{
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double cycles;
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int elems = size / sizeof(double);
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test(elems, stride); /* Warm up the cache */ //line:mem:warmup
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cycles = fcyc2(test, elems, stride, 0); /* Call test(elems,stride) */ //line:mem:fcyc
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return (size / stride) / (cycles / Mhz); /* Convert cycles to MB/s */ //line:mem:bwcompute
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}
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/* $end mountainfuns */
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