Update

src/examples/matmult.c

+/* matmult.c
+
+   Test program to do matrix multiplication on large arrays.
+
+   Intended to stress virtual memory system.
+
+   Ideally, we could read the matrices off of the file system,
+   and store the result back to the file system!
+ */
+
+#include <stdio.h>
+#include <syscall.h>
+
+/* You should define DIM to be large enough that the arrays
+   don't fit in physical memory.
+
+    Dim       Memory
+ ------     --------
+     16         3 kB
+     64        48 kB
+    128       192 kB
+    256       768 kB
+    512     3,072 kB
+  1,024    12,288 kB
+  2,048    49,152 kB
+  4,096   196,608 kB
+  8,192   786,432 kB
+ 16,384 3,145,728 kB */
+#define DIM 128
+
+int A[DIM][DIM];
+int B[DIM][DIM];
+int C[DIM][DIM];
+
+int
+main (void)
+{
+  int i, j, k;
+
+  /* Initialize the matrices. */
+  for (i = 0; i < DIM; i++)
+    for (j = 0; j < DIM; j++)
+      {
+	A[i][j] = i;
+	B[i][j] = j;
+	C[i][j] = 0;
+      }
+
+  /* Multiply matrices. */
+  for (i = 0; i < DIM; i++)
+    for (j = 0; j < DIM; j++)
+      for (k = 0; k < DIM; k++)
+	C[i][j] += A[i][k] * B[k][j];
+
+  /* Done. */
+  exit (C[DIM - 1][DIM - 1]);
+}