Exemple #1
0
// update_rate() is called from select_task() while holding a compile queue lock.
void AdvancedThresholdPolicy::update_rate(jlong t, methodOop m) {
  if (is_old(m)) {
    // We don't remove old methods from the queue,
    // so we can just zero the rate.
    m->set_rate(0);
    return;
  }

  // We don't update the rate if we've just came out of a safepoint.
  // delta_s is the time since last safepoint in milliseconds.
  jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();
  jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement
  // How many events were there since the last time?
  int event_count = m->invocation_count() + m->backedge_count();
  int delta_e = event_count - m->prev_event_count();

  // We should be running for at least 1ms.
  if (delta_s >= TieredRateUpdateMinTime) {
    // And we must've taken the previous point at least 1ms before.
    if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) {
      m->set_prev_time(t);
      m->set_prev_event_count(event_count);
      m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond
    } else
      if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) {
        // If nothing happened for 25ms, zero the rate. Don't modify prev values.
        m->set_rate(0);
      }
  }
}