BSD 4_3_Net_2 development

[unix-history] / usr / src / sys / tests / benchmarks / bench-4.1 / gausspage.c

/*
* Random page access with
* a gaussian distribution.
*
* Allocate a large (zero fill on demand) address
* space and fault the pages in a random gaussian
* order.
*/

float   sqrt(), log(), rnd(), cos(), gauss();
char    *valloc();
int     rand();

main(argc, argv)
       char *argv[];
{
       register int pn, i, niter, delta;
       register char *pages;
       float sd = 10.0;
       int npages = 4096, pagesize, debug = 0;
       char *name;

       name = argv[0];
       argc--, argv++;
again:
       if (argc < 1) {
usage:
               printf(
"usage: %s [ -d ] [ -p #pages ] [ -s standard-deviation ] iterations\n", name);
               exit(1);
       }
       if (strcmp(*argv, "-s") == 0) {
               argc--, argv++;
               if (argc < 1)
                       goto usage;
               sscanf(*argv, "%f", &sd);
               if (sd <= 0) {
                       printf("%s: Bad standard deviation.\n", *argv);
                       exit(2);
               }
               argc--, argv++;
               goto again;
       }
       if (strcmp(*argv, "-p") == 0) {
               argc--, argv++;
               if (argc < 1)
                       goto usage;
               npages = atoi(*argv);
               if (npages <= 0) {
                       printf("%s: Bad page count.\n", *argv);
                       exit(2);
               }
               argc--, argv++;
               goto again;
       }
       if (strcmp(*argv, "-d") == 0) {
               argc--, argv++;
               debug++;
               goto again;
       }
       niter = atoi(*argv);
       pagesize = getpagesize();
       pages = valloc(npages*pagesize);
       if (pages == (char *)0) {
               printf("Can't allocate %d pages (%2.1f megabytes).\n",
                   npages, (npages*pagesize) / (1024. * 1024.));
               exit(3);
       }
       pn = 0;
       for (i = 0; i < niter; i++) {
               delta = gauss(sd, 0.0);
               while (pn + delta < 0 || pn + delta > npages)
                       delta = gauss(sd, 0.0);
               pn += delta;
               if (debug)
                       printf("touch page %d\n", pn);
               else
                       pages[pn * pagesize] = 1;
       }
}

float
gauss(sd, mean)
       float sd, mean;
{
       register float qa, qb;

       qa = sqrt(log(rnd()) * -2.0);
       qb = 3.14159 * rnd();
       return (qa * cos(qb) * sd + mean);
}

float
rnd()
{
       static int seed = 1;
       static int biggest = 0x7fffffff;

       return ((float)rand(seed) / (float)biggest);
}