root/user/uw-testbin/tlbfaulter/tlbfaulter.c

DEFINITIONS

1. main

   1 /* 
   2  * tlbfaulter.c
   3  *
   4  *      This program creates an array larger than the TLB footprint,
   5  *      but hopefully smaller than memory.
   6  *      It first touches each page of the array once, which should cause
   7  *      each page to be loaded into memory.
   8  *      Then it touches the pages sequentially in a tight loop - the
   9  *      goal is to force the TLB to be filled quickly, so that TLB
  10  *      replacements will be necessary.
  11  *
  12  *      If this generates "out of memory" errors, you will need
  13  *      to increase the memory size of the machine (in sys161.conf)
  14  *      to run this test.
  15  */
  17 #include <stdio.h>
  18 #include <stdlib.h>
  20 /* 
  21  * set these to match the page size of the 
  22  * machine and the number of entries in the TLB
  23  */
  24 #define PageSize  4096
  25 #define TLBSize     64
  27 /* an array a bit larger than the size of the TLB footprint */
  28 #define ArraySize ((TLBSize+5)*PageSize)
  29 char tlbtest[ArraySize];
  31 int
main()
  33 {
  34         int i,j;
printf("Starting the tlbfaulter program\n");
  38         /* load up the array */
  39         for (i=0; i<ArraySize; i++) {
tlbtest[i]= 'a';
  41         }
printf("tlbfaulter: array initialization completed\n");
  45         /* touch one array entry on each page, sequentially, 5 times */
  46         for(j=0; j<5; j++) {
  47           for (i=0; i<ArraySize; i+=PageSize) {
tlbtest[i] += 1;
  49           }
  50         }
printf("tlbfaulter: array updates completed\n");
  54         /* check the array values we updated */
  55         for (i=0; i<ArraySize; i+=PageSize) {
  56           if (tlbtest[i] != ('a'+5)) {
printf("Test failed! Unexpected value at array position %d\n", i);
  58             return(1);
  59           }
  60         }
printf("SUCCESS\n");
  64         return 0;
  65 }