1 files changed, 124 insertions, 0 deletions
diff --git a/src/tests/threads/mlfqs-fair.c b/src/tests/threads/mlfqs-fair.c
new file mode 100644
index 0000000..3b1bea5
--- /dev/null
+++ b/src/tests/threads/mlfqs-fair.c
@@ -0,0 +1,124 @@
+/* Measures the correctness of the "nice" implementation.
+
+   The "fair" tests run either 2 or 20 threads all niced to 0.
+   The threads should all receive approximately the same number
+   of ticks.  Each test runs for 30 seconds, so the ticks should
+   also sum to approximately 30 * 100 == 3000 ticks.
+
+   The mlfqs-nice-2 test runs 2 threads, one with nice 0, the
+   other with nice 5, which should receive 1,904 and 1,096 ticks,
+   respectively, over 30 seconds.
+
+   The mlfqs-nice-10 test runs 10 threads with nice 0 through 9.
+   They should receive 672, 588, 492, 408, 316, 232, 152, 92, 40,
+   and 8 ticks, respectively, over 30 seconds.
+
+   (The above are computed via simulation in mlfqs.pm.) */
+
+#include <stdio.h>
+#include <inttypes.h>
+#include "tests/threads/tests.h"
+#include "threads/init.h"
+#include "threads/malloc.h"
+#include "threads/palloc.h"
+#include "threads/synch.h"
+#include "threads/thread.h"
+#include "devices/timer.h"
+
+static void test_mlfqs_fair (int thread_cnt, int nice_min, int nice_step);
+
+void
+test_mlfqs_fair_2 (void) 
+{
+  test_mlfqs_fair (2, 0, 0);
+}
+
+void
+test_mlfqs_fair_20 (void) 
+{
+  test_mlfqs_fair (20, 0, 0);
+}
+
+void
+test_mlfqs_nice_2 (void) 
+{
+  test_mlfqs_fair (2, 0, 5);
+}
+
+void
+test_mlfqs_nice_10 (void) 
+{
+  test_mlfqs_fair (10, 0, 1);
+}
+
+#define MAX_THREAD_CNT 20
+
+struct thread_info 
+  {
+    int64_t start_time;
+    int tick_count;
+    int nice;
+  };
+
+static void load_thread (void *aux);
+
+static void
+test_mlfqs_fair (int thread_cnt, int nice_min, int nice_step)
+{
+  struct thread_info info[MAX_THREAD_CNT];
+  int64_t start_time;
+  int nice;
+  int i;
+
+  ASSERT (thread_mlfqs);
+  ASSERT (thread_cnt <= MAX_THREAD_CNT);
+  ASSERT (nice_min >= -10);
+  ASSERT (nice_step >= 0);
+  ASSERT (nice_min + nice_step * (thread_cnt - 1) <= 20);
+
+  thread_set_nice (-20);
+
+  start_time = timer_ticks ();
+  msg ("Starting %d threads...", thread_cnt);
+  nice = nice_min;
+  for (i = 0; i < thread_cnt; i++) 
+    {
+      struct thread_info *ti = &info[i];
+      char name[16];
+
+      ti->start_time = start_time;
+      ti->tick_count = 0;
+      ti->nice = nice;
+
+      snprintf(name, sizeof name, "load %d", i);
+      thread_create (name, PRI_DEFAULT, load_thread, ti);
+
+      nice += nice_step;
+    }
+  msg ("Starting threads took %"PRId64" ticks.", timer_elapsed (start_time));
+
+  msg ("Sleeping 40 seconds to let threads run, please wait...");
+  timer_sleep (40 * TIMER_FREQ);
+  
+  for (i = 0; i < thread_cnt; i++)
+    msg ("Thread %d received %d ticks.", i, info[i].tick_count);
+}
+
+static void
+load_thread (void *ti_) 
+{
+  struct thread_info *ti = ti_;
+  int64_t sleep_time = 5 * TIMER_FREQ;
+  int64_t spin_time = sleep_time + 30 * TIMER_FREQ;
+  int64_t last_time = 0;
+
+  thread_set_nice (ti->nice);
+  timer_sleep (sleep_time - timer_elapsed (ti->start_time));
+  while (timer_elapsed (ti->start_time) < spin_time) 
+    {
+      int64_t cur_time = timer_ticks ();
+      if (cur_time != last_time)
+        ti->tick_count++;
+      last_time = cur_time;
+    }
+}