1 files changed, 149 insertions, 0 deletions

diff --git a/pintos-progos/tests/vm/parallel-merge.c b/pintos-progos/tests/vm/parallel-merge.c
new file mode 100644
index 0000000..cc09bb1
--- /dev/null
+++ b/pintos-progos/tests/vm/parallel-merge.c
@@ -0,0 +1,149 @@
+/* Generates about 1 MB of random data that is then divided into
+   16 chunks.  A separate subprocess sorts each chunk; the
+   subprocesses run in parallel.  Then we merge the chunks and
+   verify that the result is what it should be. */
+
+#include "tests/vm/parallel-merge.h"
+#include <stdio.h>
+#include <syscall.h>
+#include "tests/arc4.h"
+#include "tests/lib.h"
+#include "tests/main.h"
+
+#define CHUNK_SIZE (128 * 1024)
+#define CHUNK_CNT 8                             /* Number of chunks. */
+#define DATA_SIZE (CHUNK_CNT * CHUNK_SIZE)      /* Buffer size. */
+
+unsigned char buf1[DATA_SIZE], buf2[DATA_SIZE];
+size_t histogram[256];
+
+/* Initialize buf1 with random data,
+   then count the number of instances of each value within it. */
+static void
+init (void) 
+{
+  struct arc4 arc4;
+  size_t i;
+
+  msg ("init");
+
+  arc4_init (&arc4, "foobar", 6);
+  arc4_crypt (&arc4, buf1, sizeof buf1);
+  for (i = 0; i < sizeof buf1; i++)
+    histogram[buf1[i]]++;
+}
+
+/* Sort each chunk of buf1 using SUBPROCESS,
+   which is expected to return EXIT_STATUS. */
+static void
+sort_chunks (const char *subprocess, int exit_status)
+{
+  pid_t children[CHUNK_CNT];
+  size_t i;
+
+  for (i = 0; i < CHUNK_CNT; i++) 
+    {
+      char fn[128];
+      char cmd[128];
+      int handle;
+
+      msg ("sort chunk %zu", i);
+
+      /* Write this chunk to a file. */
+      snprintf (fn, sizeof fn, "buf%zu", i);
+      create (fn, CHUNK_SIZE);
+      quiet = true;
+      CHECK ((handle = open (fn)) > 1, "open \"%s\"", fn);
+      write (handle, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
+      close (handle);
+
+      /* Sort with subprocess. */
+      snprintf (cmd, sizeof cmd, "%s %s", subprocess, fn);
+      CHECK ((children[i] = exec (cmd)) != -1, "exec \"%s\"", cmd);
+      quiet = false;
+    }
+
+  for (i = 0; i < CHUNK_CNT; i++) 
+    {
+      char fn[128];
+      int handle;
+
+      CHECK (wait (children[i]) == exit_status, "wait for child %zu", i);
+
+      /* Read chunk back from file. */
+      quiet = true;
+      snprintf (fn, sizeof fn, "buf%zu", i);
+      CHECK ((handle = open (fn)) > 1, "open \"%s\"", fn);
+      read (handle, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
+      close (handle);
+      quiet = false;
+    }
+}
+
+/* Merge the sorted chunks in buf1 into a fully sorted buf2. */
+static void
+merge (void) 
+{
+  unsigned char *mp[CHUNK_CNT];
+  size_t mp_left;
+  unsigned char *op;
+  size_t i;
+
+  msg ("merge");
+
+  /* Initialize merge pointers. */
+  mp_left = CHUNK_CNT;
+  for (i = 0; i < CHUNK_CNT; i++)
+    mp[i] = buf1 + CHUNK_SIZE * i;
+
+  /* Merge. */
+  op = buf2;
+  while (mp_left > 0) 
+    {
+      /* Find smallest value. */
+      size_t min = 0;
+      for (i = 1; i < mp_left; i++)
+        if (*mp[i] < *mp[min])
+          min = i;
+
+      /* Append value to buf2. */
+      *op++ = *mp[min];
+
+      /* Advance merge pointer.
+         Delete this chunk from the set if it's emptied. */
+      if ((++mp[min] - buf1) % CHUNK_SIZE == 0) 
+        mp[min] = mp[--mp_left];
+    }
+}
+
+static void
+verify (void) 
+{
+  size_t buf_idx;
+  size_t hist_idx;
+
+  msg ("verify");
+
+  buf_idx = 0;
+  for (hist_idx = 0; hist_idx < sizeof histogram / sizeof *histogram;
+       hist_idx++)
+    {
+      while (histogram[hist_idx]-- > 0) 
+        {
+          if (buf2[buf_idx] != hist_idx)
+            fail ("bad value %d in byte %zu", buf2[buf_idx], buf_idx);
+          buf_idx++;
+        } 
+    }
+
+  msg ("success, buf_idx=%'zu", buf_idx);
+}
+
+void
+parallel_merge (const char *child_name, int exit_status)
+{
+  init ();
+  sort_chunks (child_name, exit_status);
+  merge ();
+  verify ();
+}