C++ TaskSet::get_utilization方法代码示例

bool FFDBFGedf::is_schedulable(const TaskSet &ts,
                               bool check_preconditions)
{
    if (m < 2)
        return false;

    if (check_preconditions)
	{
        if (!(ts.has_only_feasible_tasks() &&
              ts.is_not_overutilized(m) &&
              ts.has_only_constrained_deadlines() &&
              ts.has_no_self_suspending_tasks()))
            return false;
    }

    // allocate helpers
    AllTestPoints testing_set(ts);
    integral_t *q = new integral_t[ts.get_task_count()];
    fractional_t *r = new fractional_t[ts.get_task_count()];

    fractional_t sigma_bound;
    fractional_t time_bound;
    fractional_t tmp(1, epsilon_denom);

    // compute sigma bound
    tmp = 1;
    tmp /= epsilon_denom;
    ts.get_utilization(sigma_bound);
    sigma_bound -= m;
    sigma_bound /= - ((int) (m - 1)); // neg. to flip sign
    sigma_bound -= tmp; // epsilon
    sigma_bound = min(sigma_bound, fractional_t(1));

    // compute time bound
    time_bound = 0;
    for (unsigned int i = 0; i < ts.get_task_count(); i++)
        time_bound += ts[i].get_wcet();
    time_bound /= tmp; // epsilon

    fractional_t t_cur;
    fractional_t sigma_cur, sigma_nxt;
    bool schedulable;

    t_cur = 0;
    schedulable = false;

    // Start with minimum possible sigma value, then try
    // multiples of sigma_step.
    ts.get_max_density(sigma_cur);

    // setup brute force sigma value range
    sigma_nxt = sigma_cur / sigma_step;
    truncate_fraction(sigma_nxt);
    sigma_nxt += 1;
    sigma_nxt *= sigma_step;

    while (!schedulable &&
           sigma_cur <= sigma_bound &&
           t_cur <= time_bound)
    {
        testing_set.init(sigma_cur, t_cur);
        do {
            testing_set.get_next(t_cur);
            if (t_cur <= time_bound)
            {
                compute_q_r(ts, t_cur, q, r);
                schedulable = witness_condition(ts, q, r, t_cur, sigma_cur);
            }
            else
                // exceeded testing interval
                schedulable = true;
        } while (t_cur <= time_bound && schedulable);

        if (!schedulable && t_cur <= time_bound)
        {
            // find next sigma variable
            do
            {
                sigma_cur = sigma_nxt;
                sigma_nxt += sigma_step;
            } while (sigma_cur <= sigma_bound &&
                     !witness_condition(ts, q, r, t_cur, sigma_cur));
        }
    }

    delete [] q;
    delete [] r;

    return schedulable;
}

bool BaruahGedf::is_schedulable(const TaskSet &ts,
                                bool check_preconditions)
{
    if (check_preconditions)
    {
        if (!(ts.has_only_feasible_tasks() &&
                ts.is_not_overutilized(m) &&
                ts.has_only_constrained_deadlines()))
            return false;

        if (ts.get_task_count() == 0)
            return true;
    }

    fractional_t m_minus_u;
    ts.get_utilization(m_minus_u);
    m_minus_u *= -1;
    m_minus_u += m;

    if (m_minus_u <= 0) {
        // Baruah's G-EDF test requires strictly positive slack.
        // In the case of zero slack the testing interval becomes
        // infinite. Therefore, we can't do anything but bail out.
        return false;
    }

    double start_time = get_cpu_usage();

    integral_t i1, sum;
    integral_t *max_test_point, *idiff;
    integral_t** ptr; // indirect access to idiff

    idiff          = new integral_t[ts.get_task_count()];
    max_test_point = new integral_t[ts.get_task_count()];
    ptr            = new integral_t*[ts.get_task_count()];
    for (unsigned int i = 0; i < ts.get_task_count(); i++)
        ptr[i] = idiff + i;

    get_max_test_points(ts, m_minus_u, max_test_point);

    integral_t ilen;
    bool point_in_range = true;
    bool schedulable = true;

    AllDBFPointsOfChange *all_pts;

    all_pts = new AllDBFPointsOfChange[ts.get_task_count()];
    for (unsigned int k = 0; k < ts.get_task_count() && schedulable; k++)
        all_pts[k].init(ts, k, max_test_point + k);

    // for every task for which point <= max_ak
    unsigned long iter_count = 0;
    while (point_in_range && schedulable)
    {
        point_in_range = false;
        // check for excessive run time every 10 iterations
        if (++iter_count % 10 == 0 && get_cpu_usage() > start_time + MAX_RUNTIME)
        {
            // This is taking too long. Give up.
            schedulable = false;
            break;
        }
        for (unsigned int k = 0; k < ts.get_task_count() && schedulable; k++)
            if (all_pts[k].get_next(ilen))
            {
                schedulable = is_task_schedulable(k, ts, ilen, i1, sum,
                                                  idiff, ptr);
                point_in_range = true;
            }
    }


    delete[] all_pts;
    delete[] max_test_point;
    delete[] idiff;
    delete[] ptr;

    return schedulable;
}