root/user/testbin/ctest/ctest.c

DEFINITIONS

1. main

   1 /*
   2  * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
   3  *      The President and Fellows of Harvard College.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  30 /*
  31  * Performance test from former 161 prof. Brad Chen
  32  * Stresses VM.
  33  *
  34  * Intended for the VM assignment. This should run successfully on a
  35  * variety of strides when the VM system is complete. Strides that are
  36  * not a multiple of 2 work better; see below.
  37  */
  39 #include <stdio.h>
  40 #include <stdlib.h>
  42 /*
  43  * SIZE is the amount of memory used.
  44  * DEFAULT is the default stride.
  45  * Note that SIZE and DEFAULT should be relatively prime.
  46  */
  47 #define SIZE      (1024*1024/sizeof(struct entry))
  48 #define DEFAULT   477
  50 struct entry {
  51         struct entry *e;
  52 };
  54 struct entry array[SIZE];
  56 int
main(int argc, char **argv)
  58 {
  59         volatile struct entry *e;
  60         unsigned i, stride;
stride = DEFAULT;
  63         if (argc == 2) {
stride = atoi(argv[1]);
  65         }
  66         if (stride <= 0 || argc > 2) {
printf("Usage: ctest [stridesize]\n");
printf("   stridesize should not be a multiple of 2.\n");
  69                 return 1;
  70         }
printf("Starting ctest: stride %d\n", stride);
  74         /*
  75          * Generate a huge linked list, with each entry pointing to
  76          * the slot STRIDE entries above it. As long as STRIDE and SIZE
  77          * are relatively prime, this will put all the entries on one
  78          * list. Otherwise you will get multiple disjoint lists. (All
  79          * these lists will be circular.)
  80          */
  81         for (i=0; i<SIZE; i++) {
array[i].e = &array[(i+stride) % SIZE];
  83         }
  85         /*
  86          * Traverse the list. We stop after hitting each element once.
  87          *
  88          * (If STRIDE was even, this will hit some elements more than 
  89          * once and others not at all.)
  90          */
e = &array[0];
  92         for (i=0; i<SIZE; i++) {
  93                 if (i % stride == 0) {
putchar('.');
  95                 }
e = e->e;
  97         }
printf("\nDone!\n");
 100         return 0;
 101 }