+/* Creates N threads, each of which sleeps a different, fixed
+ duration, M times. Records the wake-up order and verifies
+ that it is valid. */
+
+#include <stdio.h>
+#include "tests/threads/tests.h"
+#include "threads/init.h"
+#include "threads/malloc.h"
+#include "threads/synch.h"
+#include "threads/thread.h"
+#include "devices/timer.h"
+
+static void test_sleep (int thread_cnt, int iterations);
+
+void
+test_alarm_simultaneous (void)
+{
+ test_sleep (5, 5);
+}
+
+/* Information about the test. */
+struct sleep_test
+ {
+ int64_t start; /* Current time at start of test. */
+ int iterations; /* Number of iterations per thread. */
+ int *output_pos; /* Current position in output buffer. */
+ };
+
+static void sleeper (void *);
+
+/* Runs THREAD_CNT threads thread sleep ITERATIONS times each. */
+static void
+test_sleep (int thread_cnt, int iterations)
+{
+ struct sleep_test test;
+ int *output;
+ int i;
+
+ /* This test does not work with the MLFQS. */
+ ASSERT (!enable_mlfqs);
+
+ msg ("Creating %d threads to sleep %d times each.", thread_cnt, iterations);
+ msg ("Each thread sleeps 10 ticks each time.");
+ msg ("Within an iteration, all threads should wake up on the same tick.");
+
+ /* Allocate memory. */
+ output = malloc (sizeof *output * iterations * thread_cnt * 2);
+ if (output == NULL)
+ PANIC ("couldn't allocate memory for test");
+
+ /* Initialize test. */
+ test.start = timer_ticks () + 100;
+ test.iterations = iterations;
+ test.output_pos = output;
+
+ /* Start threads. */
+ ASSERT (output != NULL);
+ for (i = 0; i < thread_cnt; i++)
+ {
+ char name[16];
+ snprintf (name, sizeof name, "thread %d", i);
+ thread_create (name, PRI_DEFAULT, sleeper, &test);
+ }
+
+ /* Wait long enough for all the threads to finish. */
+ timer_sleep (100 + iterations * 10 + 100);
+
+ /* Print completion order. */
+ msg ("iteration 0, thread 0: woke up after %d ticks", output[0]);
+ for (i = 1; i < test.output_pos - output; i++)
+ msg ("iteration %d, thread %d: woke up %d ticks later",
+ i / thread_cnt, i % thread_cnt, output[i] - output[i - 1]);
+
+ free (output);
+}
+
+/* Sleeper thread. */
+static void
+sleeper (void *test_)
+{
+ struct sleep_test *test = test_;
+ int i;
+
+ /* Make sure we're at the beginning of a timer tick. */
+ timer_sleep (1);
+
+ for (i = 1; i <= test->iterations; i++)
+ {
+ int64_t sleep_until = test->start + i * 10;
+ timer_sleep (sleep_until - timer_ticks ());
+ *test->output_pos++ = timer_ticks () - test->start;
+ thread_yield ();
+ }
+}