alarm-wait.c

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/** 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_single (void) 
{
  test_sleep (5, 1);
}
 
void
test_alarm_multiple (void) 
{
  test_sleep (5, 7);
}

/** Information about the test. */
struct sleep_test 
  {
    int64_t start;              /**< Current time at start of test. */
    int iterations;             /**< Number of iterations per thread. */
 
    /* Output. */
    struct lock output_lock;    /**< Lock protecting output buffer. */
    int *output_pos;            /**< Current position in output buffer. */
  };
 
/** Information about an individual thread in the test. */
struct sleep_thread 
  {
    struct sleep_test *test;     /**< Info shared between all threads. */
    int id;                     /**< Sleeper ID. */
    int duration;               /**< Number of ticks to sleep. */
    int iterations;             /**< Iterations counted so far. */
  };
 
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;
  struct sleep_thread *threads;
  int *output, *op;
  int product;
  int i;
 
  /* This test does not work with the MLFQS. */
  ASSERT (!thread_mlfqs);
 
  msg ("Creating %d threads to sleep %d times each.", thread_cnt, iterations);
  msg ("Thread 0 sleeps 10 ticks each time,");
  msg ("thread 1 sleeps 20 ticks each time, and so on.");
  msg ("If successful, product of iteration count and");
  msg ("sleep duration will appear in nondescending order.");
 
  /* Allocate memory. */
  threads = malloc (sizeof *threads * thread_cnt);
  output = malloc (sizeof *output * iterations * thread_cnt * 2);
  if (threads == NULL || output == NULL)
    PANIC ("couldn't allocate memory for test");
 
  /* Initialize test. */
  test.start = timer_ticks () + 100;
  test.iterations = iterations;
  lock_init (&test.output_lock);
  test.output_pos = output;
 
  /* Start threads. */
  ASSERT (output != NULL);
  for (i = 0; i < thread_cnt; i++)
    {
      struct sleep_thread *t = threads + i;
      char name[16];
      
      t->test = &test;
      t->id = i;
      t->duration = (i + 1) * 10;
      t->iterations = 0;
 
      snprintf (name, sizeof name, "thread %d", i);
      thread_create (name, PRI_DEFAULT, sleeper, t);
    }
  
  /* Wait long enough for all the threads to finish. */
  timer_sleep (100 + thread_cnt * iterations * 10 + 100);
 
  /* Acquire the output lock in case some rogue thread is still
     running. */
  lock_acquire (&test.output_lock);
 
  /* Print completion order. */
  product = 0;
  for (op = output; op < test.output_pos; op++) 
    {
      struct sleep_thread *t;
      int new_prod;
 
      ASSERT (*op >= 0 && *op < thread_cnt);
      t = threads + *op;
 
      new_prod = ++t->iterations * t->duration;
        
      msg ("thread %d: duration=%d, iteration=%d, product=%d",
           t->id, t->duration, t->iterations, new_prod);
      
      if (new_prod >= product)
        product = new_prod;
      else
        fail ("thread %d woke up out of order (%d > %d)!",
              t->id, product, new_prod);
    }
 
  /* Verify that we had the proper number of wakeups. */
  for (i = 0; i < thread_cnt; i++)
    if (threads[i].iterations != iterations)
      fail ("thread %d woke up %d times instead of %d",
            i, threads[i].iterations, iterations);
  
  lock_release (&test.output_lock);
  free (output);
  free (threads);
}
 
/** Sleeper thread. */
static void
sleeper (void *t_) 
{
  struct sleep_thread *t = t_;
  struct sleep_test *test = t->test;
  int i;
 
  for (i = 1; i <= test->iterations; i++) 
    {
      int64_t sleep_until = test->start + i * t->duration;
      timer_sleep (sleep_until - timer_ticks ());
      lock_acquire (&test->output_lock);
      *test->output_pos++ = t->id;
      lock_release (&test->output_lock);
    }
}