#include <vppinfra/time.h>
#include <vppinfra/cache.h>
#include <vppinfra/error.h>
#include <vppinfra/tw_timer_2t_1w_2048sl.h>
#include <vppinfra/tw_timer_2t_2w_512sl.h>
#include <vppinfra/tw_timer_16t_2w_512sl.h>
#include <vppinfra/tw_timer_4t_3w_256sl.h>
#include <vppinfra/tw_timer_1t_3w_1024sl_ov.h>

typedef struct
{
  /** Handle returned from tw_start_timer */
  u32 stop_timer_handle;

  /** Test item should expire at this clock tick */
  u64 expected_to_expire;
} tw_timer_test_elt_t;

typedef struct
{
  /** Pool of test objects */
  tw_timer_test_elt_t *test_elts;

  /** The single-wheel */
  tw_timer_wheel_2t_1w_2048sl_t single_wheel;

  /** The double-wheel */
  tw_timer_wheel_16t_2w_512sl_t double_wheel;

  /* The triple wheel */
  tw_timer_wheel_4t_3w_256sl_t triple_wheel;

  /* The triple wheel with overflow vector */
  tw_timer_wheel_1t_3w_1024sl_ov_t triple_ov_wheel;

  /* Another two timer wheel geometry */
  tw_timer_wheel_2t_2w_512sl_t two_timer_double_wheel;

  /** random number seed */
  u64 seed;

  /** number of timers */
  u32 ntimers;

  /** number of "churn" iterations */
  u32 niter;

  /** number of clock ticks per churn iteration */
  u32 ticks_per_iter;

  /** cpu timer */
  clib_time_t clib_time;
} tw_timer_test_main_t;

tw_timer_test_main_t tw_timer_test_main;

static void
run_single_wheel (tw_timer_wheel_2t_1w_2048sl_t * tw, u32 n_ticks)
{
  u32 i;
  f64 now = tw->last_run_time + 1.01;

  for (i = 0; i < n_ticks; i++)
    {
      tw_timer_expire_timers_2t_1w_2048sl (tw, now);
      now += 1.01;
    }
}

static void
run_double_wheel (tw_timer_wheel_16t_2w_512sl_t * tw, u32 n_ticks)
{
  u32 i;
  f64 now = tw->last_run_time + 1.01;

  for (i = 0; i < n_ticks; i++)
    {
      tw_timer_expire_timers_16t_2w_512sl (tw, now);
      now += 1.01;
    }
}

static void
run_two_timer_double_wheel (tw_timer_wheel_2t_2w_512sl_t * tw, u32 n_ticks)
{
  u32 i;
  f64 now = tw->last_run_time + 1.01;

  for (i = 0; i < n_ticks; i++)
    {
      tw_timer_expire_timers_2t_2w_512sl (tw, now);
      now += 1.01;
    }
}

static void
run_triple_wheel (tw_timer_wheel_4t_3w_256sl_t * tw, u32 n_ticks)
{
  u32 i;
  f64 now = tw->last_run_time + 1.01;

  for (i = 0; i < n_ticks; i++)
    {
      tw_timer_expire_timers_4t_3w_256sl (tw, now);
      now += 1.01;
    }
}

static void
run_triple_ov_wheel (tw_timer_wheel_1t_3w_1024sl_ov_t * tw, u32 n_ticks)
{
  u32 i;
  f64 now = tw->last_run_time + 1.01;

  for (i = 0; i < n_ticks; i++)
    {
      tw_timer_expire_timers_1t_3w_1024sl_ov (tw, now);
      now += 1.01;
    }
}

static void
expired_timer_single_callback (u32 * expired_timers)
{
  int i;
  u32 pool_index, timer_id;
  tw_timer_test_elt_t *e;
  tw_timer_test_main_t *tm = &tw_timer_test_main;

  for (i = 0; i < vec_len (expired_timers); i++)
    {
      pool_index = expired_timers[i] & 0x7FFFFFFF;
      timer_id = expired_timers[i] >> 31;

      ASSERT (timer_id == 1);

      e = pool_elt_at_index (tm->test_elts, pool_index);

      if (e->expected_to_expire != tm->single_wheel.current_tick)
	{
	  fformat (stdout, "[%d] expired at %lld not %lld\n",
		   e - tm->test_elts, tm->single_wheel.current_tick,
		   e->expected_to_expire);
	}
      pool_put (tm->test_elts, e);
    }
}

static void
expired_timer_double_callback (u32 * expired_timers)
{
  int i;
  u32 pool_index, timer_id;
  tw_timer_test_elt_t *e;
  tw_timer_test_main_t *tm = &tw_timer_test_main;

  for (i = 0; i < vec_len (expired_timers); i++)
    {
      pool_index = expired_timers[i] & 0x0FFFFFFF;
      timer_id = expired_timers[i] >> 28;

      ASSERT (timer_id == 14);

      e = pool_elt_at_index (tm->test_elts, pool_index);

      if (e->expected_to_expire != tm->double_wheel.current_tick)
	{
	  fformat (stdout, "[%d] expired at %lld not %lld\n",
		   e - tm->test_elts, tm->double_wheel.current_tick,
		   e->expected_to_expire);
	}
      pool_put (tm->test_elts, e);
    }
}

static void
expired_timer_two_timer_double_callback (u32 * expired_timers)
{
  int i;
  u32 pool_index, timer_id;
  tw_timer_test_elt_t *e;
  tw_timer_test_main_t *tm = &tw_timer_test_main;

  for (i = 0; i < vec_len (expired_timers); i++)
    {
      pool_index = expired_timers[i] & 0x7FFFFFFF;
      timer_id = expired_timers[i] >> 31;

      ASSERT (timer_id == 1);

      e = pool_elt_at_index (tm->test_elts, pool_index);

      if (e->expected_to_expire != tm->two_timer_double_wheel.current_tick)
	{
	  fformat (stdout, "[%d] expired at %lld not %lld\n",
		   e - tm->test_elts, tm->two_timer_double_wheel.current_tick,
		   e->expected_to_expire);
	}
      pool_put (tm->test_elts, e);
    }
}

static void
expired_timer_triple_callback (u32 * expired_timers)
{
  int i;
  u32 pool_index, timer_id;
  tw_timer_test_elt_t *e;
  tw_timer_test_main_t *tm = &tw_timer_test_main;

  for (i = 0; i < vec_len (expired_timers); i++)
    {
      pool_index = expired_timers[i] & 0x3FFFFFFF;
      timer_id = expired_timers[i] >> 30;

      ASSERT (timer_id == 3);

      e = pool_elt_at_index (tm->test_elts, pool_index);

      if (e->expected_to_expire != tm->triple_wheel.current_tick)
	{
	  fformat (stdout, "[%d] expired at %lld not %lld\n",
		   e - tm->test_elts, tm->triple_wheel.current_tick,
		   e->expected_to_expire);
	}
      pool_put (tm->test_elts, e);
    }
}

static void
expired_timer_triple_ov_callback (u32 * expired_timers)
{
  int i;
  u32 pool_index;
  tw_timer_test_elt_t *e;
  tw_timer_test_main_t *tm = &tw_timer_test_main;

  for (i = 0; i < vec_len (expired_timers); i++)
    {
      pool_index = expired_timers[i];

      e = pool_elt_at_index (tm->test_elts, pool_index);

      if (e->expected_to_expire != tm->triple_ov_wheel.current_tick)
	{
	  fformat (stdout, "[%d] expired at %lld not %lld\n",
		   e - tm->test_elts, tm->triple_ov_wheel.current_tick,
		   e->expected_to_expire);
	}
      pool_put (tm->test_elts, e);
    }
}

static clib_error_t *
test2_single (tw_timer_test_main_t * tm)
{
  u32 i, j;
  tw_timer_test_elt_t *e;
  u32 initial_wheel_offset;
  u64 expiration_time;
  u32 max_expiration_time = 0;
  u32 *deleted_indices = 0;
  u32 adds = 0, deletes = 0;
  f64 before, after;

  clib_time_init (&tm->clib_time);

  tw_timer_wheel_init_2t_1w_2048sl (&tm->single_wheel,
				    expired_timer_single_callback,
				    1.0 /* timer interval */ , ~0);

  /* Prime offset */
  initial_wheel_offset = 757;

  run_single_wheel (&tm->single_wheel, initial_wheel_offset);

  fformat (stdout, "initial wheel time %d, fast index %d\n",
	   tm->single_wheel.current_tick,
	   tm->single_wheel.current_index[TW_TIMER_RING_FAST]);

  initial_wheel_offset = tm->single_wheel.current_tick;

  fformat (stdout,
	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);

  before = clib_time_now (&tm->clib_time);

  /* Prime the pump */
  for (i = 0; i < tm->ntimers; i++)
    {
      pool_get (tm->test_elts, e);
      clib_memset (e, 0, sizeof (*e));

      do
	{
	  expiration_time = random_u64 (&tm->seed) & (2047);
	}
      while (expiration_time == 0);

      if (expiration_time > max_expiration_time)
	max_expiration_time = expiration_time;

      e->expected_to_expire = expiration_time + initial_wheel_offset;
      e->stop_timer_handle =
	tw_timer_start_2t_1w_2048sl (&tm->single_wheel, e - tm->test_elts,
				     1 /* timer id */ ,
				     expiration_time);
    }

  adds += i;

  for (i = 0; i < tm->niter; i++)
    {
      run_single_wheel (&tm->single_wheel, tm->ticks_per_iter);

      j = 0;
      vec_reset_length (deleted_indices);
      /* *INDENT-OFF* */
      pool_foreach (e, tm->test_elts)
       {
        tw_timer_stop_2t_1w_2048sl (&tm->single_wheel, e->stop_timer_handle);
        vec_add1 (deleted_indices, e - tm->test_elts);
        if (++j >= tm->ntimers / 4)
          goto del_and_re_add;
      }
      /* *INDENT-ON* */

    del_and_re_add:
      for (j = 0; j < vec_len (deleted_indices); j++)
	{
	  pool_put_index (tm->test_elts, deleted_indices[j]);
	}

      deletes += j;

      for (j = 0; j < tm->ntimers / 4; j++)
	{
	  pool_get (tm->test_elts, e);
	  clib_memset (e, 0, sizeof (*e));

	  do
	    {
	      expiration_time = random_u64 (&tm->seed) & (2047);
	    }
	  while (expiration_time == 0);

	  if (expiration_time > max_expiration_time)
	    max_expiration_time = expiration_time;

	  e->expected_to_expire =
	    expiration_time + tm->single_wheel.current_tick;
	  e->stop_timer_handle = tw_timer_start_2t_1w_2048sl
	    (&tm->single_wheel, e - tm->test_elts, 1 /* timer id */ ,
	     expiration_time);
	}
      adds += j;
    }

  vec_free (deleted_indices);

  run_single_wheel (&tm->single_wheel, max_expiration_time + 1);

  after = clib_time_now (&tm->clib_time);

  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
	   tm->single_wheel.current_tick);
  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
	   (after - before),
	   ((f64) adds + (f64) deletes +
	    (f64) tm->single_wheel.current_tick) / (after - before));

  if (pool_elts (tm->test_elts))
    fformat (stdout, "Note: %d elements remain in pool\n",
	     pool_elts (tm->test_elts));

  /* *INDENT-OFF* */
  pool_foreach (e, tm->test_elts)
   {
    fformat (stdout, "[%d] expected to expire %d\n",
             e - tm->test_elts,
             e->expected_to_expire);
  }
  /* *INDENT-ON* */

  pool_free (tm->test_elts);
  tw_timer_wheel_free_2t_1w_2048sl (&tm->single_wheel);
  return 0;
}

static clib_error_t *
test2_double (tw_timer_test_main_t * tm)
{
  u32 i, j;
  tw_timer_test_elt_t *e;
  u32 initial_wheel_offset;
  u32 expiration_time;
  u32 max_expiration_time = 0;
  u32 *deleted_indices = 0;
  u32 adds = 0, deletes = 0;
  f64 before, after;

  clib_time_init (&tm->clib_time);

  tw_timer_wheel_init_16t_2w_512sl (&tm->double_wheel,
				    expired_timer_double_callback,
				    1.0 /* timer interval */ , ~0);

  /* Prime offset */
  initial_wheel_offset = 7577;

  run_double_wheel (&tm->double_wheel, initial_wheel_offset);

  fformat (stdout, "initial wheel time %d, fast index %d slow index %d\n",
	   tm->double_wheel.current_tick,
	   tm->double_wheel.current_index[TW_TIMER_RING_FAST],
	   tm->double_wheel.current_index[TW_TIMER_RING_SLOW]);

  initial_wheel_offset = tm->double_wheel.current_tick;

  fformat (stdout,
	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);

  before = clib_time_now (&tm->clib_time);

  /* Prime the pump */
  for (i = 0; i < tm->ntimers; i++)
    {
      pool_get (tm->test_elts, e);
      clib_memset (e, 0, sizeof (*e));

      do
	{
	  expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
	}
      while (expiration_time == 0);

      if (expiration_time > max_expiration_time)
	max_expiration_time = expiration_time;

      e->expected_to_expire = expiration_time + initial_wheel_offset;

      e->stop_timer_handle =
	tw_timer_start_16t_2w_512sl (&tm->double_wheel, e - tm->test_elts,
				     14 /* timer id */ ,
				     expiration_time);
    }

  adds += i;

  for (i = 0; i < tm->niter; i++)
    {
      run_double_wheel (&tm->double_wheel, tm->ticks_per_iter);

      j = 0;
      vec_reset_length (deleted_indices);
      /* *INDENT-OFF* */
      pool_foreach (e, tm->test_elts)
       {
        tw_timer_stop_16t_2w_512sl (&tm->double_wheel, e->stop_timer_handle);
        vec_add1 (deleted_indices, e - tm->test_elts);
        if (++j >= tm->ntimers / 4)
          goto del_and_re_add;
      }
      /* *INDENT-ON* */

    del_and_re_add:
      for (j = 0; j < vec_len (deleted_indices); j++)
	pool_put_index (tm->test_elts, deleted_indices[j]);

      deletes += j;

      for (j = 0; j < tm->ntimers / 4; j++)
	{
	  pool_get (tm->test_elts, e);
	  clib_memset (e, 0, sizeof (*e));

	  do
	    {
	      expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
	    }
	  while (expiration_time == 0);

	  if (expiration_time > max_expiration_time)
	    max_expiration_time = expiration_time;

	  e->expected_to_expire = expiration_time +
	    tm->double_wheel.current_tick;

	  e->stop_timer_handle = tw_timer_start_16t_2w_512sl
	    (&tm->double_wheel, e - tm->test_elts, 14 /* timer id */ ,
	     expiration_time);
	}
      adds += j;
    }

  vec_free (deleted_indices);

  run_double_wheel (&tm->double_wheel, max_expiration_time + 1);

  after = clib_time_now (&tm->clib_time);

  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
	   tm->double_wheel.current_tick);
  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
	   (after - before),
	   ((f64) adds + (f64) deletes +
	    (f64) tm->double_wheel.current_tick) / (after - before));

  if (pool_elts (tm->test_elts))
    fformat (stdout, "Note: %d elements remain in pool\n",
	     pool_elts (tm->test_elts));

  /* *INDENT-OFF* */
  pool_foreach (e, tm->test_elts)
   {
    fformat (stdout, "[%d] expected to expire %d\n",
             e - tm->test_elts,
             e->expected_to_expire);
  }
  /* *INDENT-ON* */

  pool_free (tm->test_elts);
  tw_timer_wheel_free_16t_2w_512sl (&tm->double_wheel);
  return 0;
}

static u32
get_expiration_time (tw_timer_test_main_t * tm)
{
  u32 expiration_time;
  do
    {
      expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
    }
  while (expiration_time == 0);
  return expiration_time;
}

static clib_error_t *
test2_double_updates (tw_timer_test_main_t * tm)
{
  u32 i, j;
  tw_timer_test_elt_t *e;
  u32 initial_wheel_offset;
  u32 expiration_time;
  u32 max_expiration_time = 0, updates = 0;
  f64 before, after;

  clib_time_init (&tm->clib_time);
  tw_timer_wheel_init_16t_2w_512sl (&tm->double_wheel,
				    expired_timer_double_callback,
				    1.0 /* timer interval */ , ~0);

  /* Prime offset */
  initial_wheel_offset = 7577;
  run_double_wheel (&tm->double_wheel, initial_wheel_offset);
  fformat (stdout, "initial wheel time %d, fast index %d slow index %d\n",
	   tm->double_wheel.current_tick,
	   tm->double_wheel.current_index[TW_TIMER_RING_FAST],
	   tm->double_wheel.current_index[TW_TIMER_RING_SLOW]);

  initial_wheel_offset = tm->double_wheel.current_tick;
  fformat (stdout,
	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);

  before = clib_time_now (&tm->clib_time);

  /* Prime the pump */
  for (i = 0; i < tm->ntimers; i++)
    {
      pool_get (tm->test_elts, e);
      clib_memset (e, 0, sizeof (*e));

      expiration_time = get_expiration_time (tm);
      max_expiration_time = clib_max (expiration_time, max_expiration_time);

      e->expected_to_expire = expiration_time + initial_wheel_offset;
      e->stop_timer_handle = tw_timer_start_16t_2w_512sl (&tm->double_wheel,
							  e - tm->test_elts,
							  14 /* timer id */ ,
							  expiration_time);
    }

  for (i = 0; i < tm->niter; i++)
    {
      run_double_wheel (&tm->double_wheel, tm->ticks_per_iter);

      j = 0;

      /* *INDENT-OFF* */
      pool_foreach (e, tm->test_elts)
       {
        expiration_time = get_expiration_time (tm);
        max_expiration_time = clib_max (expiration_time, max_expiration_time);
	e->expected_to_expire = expiration_time
				+ tm->double_wheel.current_tick;
        tw_timer_update_16t_2w_512sl (&tm->double_wheel, e->stop_timer_handle,
                                      expiration_time);
        if (++j >= tm->ntimers / 4)
          goto done;
      }
      /* *INDENT-ON* */

    done:
      updates += j;
    }

  run_double_wheel (&tm->double_wheel, max_expiration_time + 1);

  after = clib_time_now (&tm->clib_time);

  fformat (stdout, "%d updates, %d ticks\n", updates,
	   tm->double_wheel.current_tick);
  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
	   (after - before),
	   ((f64) updates + (f64) tm->double_wheel.current_tick) / (after -
								    before));

  if (pool_elts (tm->test_elts))
    fformat (stdout, "Note: %d elements remain in pool\n",
	     pool_elts (tm->test_elts));

  /* *INDENT-OFF* */
  pool_foreach (e, tm->test_elts)
   {
    fformat (stdout, "[%d] expected to expire %d\n",
             e - tm->test_elts,
             e->expected_to_expire);
  }
  /* *INDENT-ON* */

  pool_free (tm->test_elts);
  tw_timer_wheel_free_16t_2w_512sl (&tm->double_wheel);
  return 0;
}

static clib_error_t *
test2_triple (tw_timer_test_main_t * tm)
{
  u32 i, j;
  tw_timer_test_elt_t *e;
  u32 initial_wheel_offset = 0;
  u32 expiration_time;
  u32 max_expiration_time = 0;
  u32 *deleted_indices = 0;
  u32 adds = 0, deletes = 0;
  f64 before, after;

  clib_time_init (&tm->clib_time);

  tw_timer_wheel_init_4t_3w_256sl (&tm->triple_wheel,
				   expired_timer_triple_callback,
				   1.0 /* timer interval */ , ~0);


  /* Prime offset */
  initial_wheel_offset = 75700;
  run_triple_wheel (&tm->triple_wheel, initial_wheel_offset);

  fformat (stdout,
	   "initial wheel time %d, fi %d si %d gi %d\n",
	   tm->triple_wheel.current_tick,
	   tm->triple_wheel.current_index[TW_TIMER_RING_FAST],
	   tm->triple_wheel.current_index[TW_TIMER_RING_SLOW],
	   tm->triple_wheel.current_index[TW_TIMER_RING_GLACIER]);

  initial_wheel_offset = tm->triple_wheel.current_tick;

  fformat (stdout,
	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);

  before = clib_time_now (&tm->clib_time);

  /* Prime the pump */
  for (i = 0; i < tm->ntimers; i++)
    {
      pool_get (tm->test_elts, e);
      clib_memset (e, 0, sizeof (*e));

      do
	{
	  expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
	}
      while (expiration_time == 0);

      if (expiration_time > max_expiration_time)
	max_expiration_time = expiration_time;

      e->expected_to_expire = expiration_time + initial_wheel_offset;

      e->stop_timer_handle =
	tw_timer_start_4t_3w_256sl (&tm->triple_wheel, e - tm->test_elts,
				    3 /* timer id */ ,
				    expiration_time);
    }

  adds += i;

  for (i = 0; i < tm->niter; i++)
    {
      run_triple_wheel (&tm->triple_wheel, tm->ticks_per_iter);

      j = 0;
      vec_reset_length (deleted_indices);
      /* *INDENT-OFF* */
      pool_foreach (e, tm->test_elts)
       {
        tw_timer_stop_4t_3w_256sl (&tm->triple_wheel, e->stop_timer_handle);
        vec_add1 (deleted_indices, e - tm->test_elts);
        if (++j >= tm->ntimers / 4)
          goto del_and_re_add;
      }
      /* *INDENT-ON* */

    del_and_re_add:
      for (j = 0; j < vec_len (deleted_indices); j++)
	pool_put_index (tm->test_elts, deleted_indices[j]);

      deletes += j;

      for (j = 0; j < tm->ntimers / 4; j++)
	{
	  pool_get (tm->test_elts, e);
	  clib_memset (e, 0, sizeof (*e));

	  do
	    {
	      expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
	    }
	  while (expiration_time == 0);

	  if (expiration_time > max_expiration_time)
	    max_expiration_time = expiration_time;

	  e->expected_to_expire = expiration_time +
	    tm->triple_wheel.current_tick;

	  e->stop_timer_handle = tw_timer_start_4t_3w_256sl
	    (&tm->triple_wheel, e - tm->test_elts, 3 /* timer id */ ,
	     expiration_time);
	}
      adds += j;
    }

  vec_free (deleted_indices);

  run_triple_wheel (&tm->triple_wheel, max_expiration_time + 1);

  after = clib_time_now (&tm->clib_time);

  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
	   tm->triple_wheel.current_tick);
  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
	   (after - before),
	   ((f64) adds + (f64) deletes +
	    (f64) tm->triple_wheel.current_tick) / (after - before));

  if (pool_elts (tm->test_elts))
    fformat (stdout, "Note: %d elements remain in pool\n",
	     pool_elts (tm->test_elts));

  /* *INDENT-OFF* */
  pool_foreach (e, tm->test_elts)
   {
    fformat (stdout, "[%d] expected to expire %d\n",
             e - tm->test_elts,
             e->expected_to_expire);
  }
  /* *INDENT-ON* */

  pool_free (tm->test_elts);
  tw_timer_wheel_free_4t_3w_256sl (&tm->triple_wheel);
  return 0;
}

static clib_error_t *
test2_triple_ov (tw_timer_test_main_t * tm)
{
  u32 i, j;
  tw_timer_test_elt_t *e;
  u32 initial_wheel_offset = 0;
  u32 expiration_time;
  u32 max_expiration_time = 0;
  u32 *deleted_indices = 0;
  u32 adds = 0, deletes = 0;
  f64 before, after;

  clib_time_init (&tm->clib_time);

  tw_timer_wheel_init_1t_3w_1024sl_ov (&tm->triple_ov_wheel,
				       expired_timer_triple_ov_callback,
				       1.0 /* timer interval */ , ~0);


  /* Prime offset */
  initial_wheel_offset = 75700;
  run_triple_ov_wheel (&tm->triple_ov_wheel, initial_wheel_offset);

  fformat (stdout,
	   "initial wheel time %d, fi %d si %d gi %d\n",
	   tm->triple_ov_wheel.current_tick,
	   tm->triple_ov_wheel.current_index[TW_TIMER_RING_FAST],
	   tm->triple_ov_wheel.current_index[TW_TIMER_RING_SLOW],
	   tm->triple_ov_wheel.current_index[TW_TIMER_RING_GLACIER]);

  initial_wheel_offset = tm->triple_ov_wheel.current_tick;

  fformat (stdout,
	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);

  before = clib_time_now (&tm->clib_time);

  /* Prime the pump */
  for (i = 0; i < tm->ntimers; i++)
    {
      pool_get (tm->test_elts, e);
      clib_memset (e, 0, sizeof (*e));

      do
	{
	  expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
	}
      while (expiration_time == 0);

      if (expiration_time > max_expiration_time)
	max_expiration_time = expiration_time;

      e->expected_to_expire = expiration_time + initial_wheel_offset;

      e->stop_timer_handle =
	tw_timer_start_1t_3w_1024sl_ov (&tm->triple_ov_wheel,
					e - tm->test_elts, 0 /* timer id */ ,
					expiration_time);
    }

  adds += i;

  for (i = 0; i < tm->niter; i++)
    {
      run_triple_ov_wheel (&tm->triple_ov_wheel, tm->ticks_per_iter);

      j = 0;
      vec_reset_length (deleted_indices);
      /* *INDENT-OFF* */
      pool_foreach (e, tm->test_elts)
       {
        tw_timer_stop_1t_3w_1024sl_ov (&tm->triple_ov_wheel,
                                       e->stop_timer_handle);
        vec_add1 (deleted_indices, e - tm->test_elts);
        if (++j >= tm->ntimers / 4)
          goto del_and_re_add;
      }
      /* *INDENT-ON* */

    del_and_re_add:
      for (j = 0; j < vec_len (deleted_indices); j++)
	pool_put_index (tm->test_elts, deleted_indices[j]);

      deletes += j;

      for (j = 0; j < tm->ntimers / 4; j++)
	{
	  pool_get (tm->test_elts, e);
	  clib_memset (e, 0, sizeof (*e));

	  do
	    {
	      expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
	    }
	  while (expiration_time == 0);

	  if (expiration_time > max_expiration_time)
	    max_expiration_time = expiration_time;

	  e->expected_to_expire = expiration_time +
	    tm->triple_ov_wheel.current_tick;

	  e->stop_timer_handle = tw_timer_start_1t_3w_1024sl_ov
	    (&tm->triple_ov_wheel, e - tm->test_elts, 0 /* timer id */ ,
	     expiration_time);
	}
      adds += j;
    }

  vec_free (deleted_indices);

  run_triple_ov_wheel (&tm->triple_ov_wheel, max_expiration_time + 1);

  after = clib_time_now (&tm->clib_time);

  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
	   tm->triple_ov_wheel.current_tick);
  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
	   (after - before),
	   ((f64) adds + (f64) deletes +
	    (f64) tm->triple_ov_wheel.current_tick) / (after - before));

  if (pool_elts (tm->test_elts))
    fformat (stdout, "Note: %d elements remain in pool\n",
	     pool_elts (tm->test_elts));

  /* *INDENT-OFF* */
  pool_foreach (e, tm->test_elts)
   {
    TWT (tw_timer) * t;

    fformat (stdout, "[%d] expected to expire %d\n",
             e - tm->test_elts,
             e->expected_to_expire);
    t = pool_elt_at_index (tm->triple_ov_wheel.timers, e->stop_timer_handle);
    fformat (stdout, "  expiration_time %lld\n", t->expiration_time);
  }
  /* *INDENT-ON* */

  pool_free (tm->test_elts);
  tw_timer_wheel_free_1t_3w_1024sl_ov (&tm->triple_ov_wheel);
  return 0;
}

static clib_error_t *
test1_single (tw_timer_test_main_t * tm)
{
  u32 i;
  tw_timer_test_elt_t *e;
  u32 offset;

  tw_timer_wheel_init_2t_1w_2048sl (&tm->single_wheel,
				    expired_timer_single_callback,
				    1.0 /* timer interval */ , ~0);

  /*
   * Prime offset, to make sure that the wheel starts in a
   * non-trivial position
   */
  offset = 123;

  run_single_wheel (&tm->single_wheel, offset);

  fformat (stdout, "initial wheel time %d, fast index %d\n",
	   tm->single_wheel.current_tick,
	   tm->single_wheel.current_index[TW_TIMER_RING_FAST]);

  offset = tm->single_wheel.current_tick;

  for (i = 0; i < tm->ntimers; i++)
    {
      u32 expected_to_expire;
      u32 timer_arg;

      timer_arg = 1 + i;
      timer_arg &= 2047;
      if (timer_arg == 0)
	timer_arg = 1;

      expected_to_expire = timer_arg + tm->single_wheel.current_tick;

      pool_get (tm->test_elts, e);
      clib_memset (e, 0, sizeof (*e));
      e->expected_to_expire = expected_to_expire;
      e->stop_timer_handle = tw_timer_start_2t_1w_2048sl
	(&tm->single_wheel, e - tm->test_elts, 1 /* timer id */ ,
	 timer_arg);
    }
  run_single_wheel (&tm->single_wheel, tm->ntimers + 3);

  if (pool_elts (tm->test_elts))
    fformat (stdout, "Note: %d elements remain in pool\n",
	     pool_elts (tm->test_elts));

  /* *INDENT-OFF* */
  pool_foreach (e, tm->test_elts)
   {
    fformat(stdout, "[%d] expected to expire %d\n",
                     e - tm->test_elts,
                     e->expected_to_expire);
  }
  /* *INDENT-ON* */

  fformat (stdout,
	   "final wheel time %d, fast index %d\n",
	   tm->single_wheel.current_tick,
	   tm->single_wheel.current_index[TW_TIMER_RING_FAST]);

  pool_free (tm->test_elts);
  tw_timer_wheel_free_2t_1w_2048sl (&tm->single_wheel);
  return 0;
}

static clib_error_t *
test1_double (tw_timer_test_main_t * tm)
{
  u32 i;
  tw_timer_test_elt_t *e;
  u32 offset;

  tw_timer_wheel_init_16t_2w_512sl (&tm->double_wheel,
				    expired_timer_double_callback,
				    1.0 /* timer interval */ , ~0);

  /*
   * Prime offset, to make sure that the wheel starts in a
   * non-trivial position
   */
  offset = 227989;

  run_double_wheel (&tm->double_wheel, offset);

  fformat (stdout, "initial wheel time %d, fast index %d\n",
	   tm->double_wheel.current_tick,
	   tm->double_wheel.current_index[TW_TIMER_RING_FAST]);

  for (i = 0; i < tm->ntimers; i++)
    {
      pool_get (tm->test_elts, e);
      clib_memset (e, 0, sizeof (*e));

      e->expected_to_expire = i + tm->double_wheel.current_tick + 1;
      e->stop_timer_handle = tw_timer_start_16t_2w_512sl
	(&tm->double_wheel, e - tm->test_elts, 14 /* timer id */ ,
	 i + 1);
    }
  run_double_wheel (&tm->double_wheel, tm->ntimers + 3);

  if (pool_elts (tm->test_elts))
    fformat (stdout, "Note: %d elements remain in pool\n",
	     pool_elts (tm->test_elts));

  /* *INDENT-OFF* */
  pool_foreach (e, tm->test_elts)
   {
    fformat(stdout, "[%d] expected to expire %d\n",
                     e - tm->test_elts,
                     e->expected_to_expire);
  }
  /* *INDENT-ON* */

  fformat (stdout,
	   "final wheel time %d, fast index %d\n",
	   tm->double_wheel.current_tick,
	   tm->double_wheel.current_index[TW_TIMER_RING_FAST]);

  pool_free (tm->test_elts);
  tw_timer_wheel_free_16t_2w_512sl (&tm->double_wheel);
  return 0;
}

static clib_error_t *
test1_two_timer_double (tw_timer_test_main_t * tm)<style>
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</style><div class="highlight"><pre><span></span><span class="c1"># Copyright (c) 2022 Cisco and/or its affiliates.</span>
<span class="c1"># Licensed under the Apache License, Version 2.0 (the &quot;License&quot;);</span>
<span class="c1"># you may not use this file except in compliance with the License.</span>
<span class="c1"># You may obtain a copy of the License at:</span>
<span class="c1">#</span>
<span class="c1">#     http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="c1">#</span>
<span class="c1"># Unless required by applicable law or agreed to in writing, software</span>
<span class="c1"># distributed under the License is distributed on an &quot;AS IS&quot; BASIS,</span>
<span class="c1"># WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
<span class="c1"># See the License for the specific language governing permissions and</span>
<span class="c1"># limitations under the License.</span>

<span class="sd">&quot;&quot;&quot;Constants used in CSIT.</span>

<span class="sd">&quot;Constant&quot; means a value that keeps its value since initialization. The value</span>
<span class="sd">does not need to be hard coded here, but can be read from environment variables.</span>
<span class="sd">&quot;&quot;&quot;</span>


<span class="kn">import</span> <span class="nn">os</span>


<span class="k">def</span> <span class="nf">get_str_from_env</span><span class="p">(</span><span class="n">env_var_names</span><span class="p">,</span> <span class="n">default_value</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;Attempt to read string from environment variable, return that or default.</span>

<span class="sd">    If environment variable exists, but is empty (and default is not),</span>
<span class="sd">    empty string is returned.</span>

<span class="sd">    Several environment variable names are examined, as CSIT currently supports</span>
<span class="sd">    a mix of naming conventions.</span>
<span class="sd">    Here &quot;several&quot; means there are hard coded prefixes to try,</span>
<span class="sd">    and env_var_names itself can be single name, or a list or a tuple of names.</span>

<span class="sd">    :param env_var_names: Base names of environment variable to attempt to read.</span>
<span class="sd">    :param default_value: Value to return if the env var does not exist.</span>
<span class="sd">    :type env_var_names: str, or list of str, or tuple of str</span>
<span class="sd">    :type default_value: str</span>
<span class="s