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// -*- C++ -*-
//=============================================================================
/**
* @file CTT_Enhanced.cpp
*
* $Id$
*
* @author Friedhelm Wolf (fwolf@dre.vanderbilt.edu)
*/
//=============================================================================
#include <numeric>
#include <cmath>
#include "CTT_Enhanced.h"
CTT_Enhanced::~CTT_Enhanced ()
{
}
double
CTT_Enhanced::operator () (const TASK_LIST & tasks)
{
// copy tasks for local modifications
TASK_LIST scheduled_tasks = tasks;
// take last element and use it for schedulability analysis.
// It is assumed that all other tasks are schedulable
if (scheduled_tasks.size () > 0)
{
Task t = scheduled_tasks [scheduled_tasks.size () - 1];
scheduled_tasks.pop_back ();
double wcrt = this->worst_case_response_time_check (t, scheduled_tasks);
TRACE ("(" << tasks << ") = " << wcrt);
// return the wcrt for this task
return wcrt;
}
TRACE ("(" << tasks << ") = 0");
return .0;
}
double
CTT_Enhanced::worst_case_response_time_check (
const Task & task,
const TASK_LIST & higher_prio_tasks)
{
// determine execution time based on type of application
double exec_time = (task.role == PRIMARY ?
task.execution_time :
task.sync_time);
// R0 = C1 + C2 + ... + Cn
double R = std::accumulate (higher_prio_tasks.begin (),
higher_prio_tasks.end (),
exec_time,
AddExecutionTimes ());
// R_k = C1 + sum_j (ceil (R_k-1 / T_j) * Cj)
double R_copy = 0;
double_equal equals;
while (R <= task.period)
{
R_copy = R;
R = std::accumulate (higher_prio_tasks.begin (),
higher_prio_tasks.end (),
exec_time,
WCET_Heuristic_Step (R));
if (equals (R_copy, R))
break;
}
if (R <= task.period)
return R;
else
return .0;
}
double
CTT_Enhanced::AddExecutionTimes::operator () (double time, const Task & task)
{
// determine execution time based on type of application
double exec_time = (task.role == PRIMARY ?
task.execution_time :
task.sync_time);
return time + exec_time;
}
CTT_Enhanced::WCET_Heuristic_Step::WCET_Heuristic_Step (double R)
: R_ (R)
{
}
double
CTT_Enhanced::WCET_Heuristic_Step::operator () (double time, const Task & task)
{
// determine execution time based on type of application
double exec_time = (task.role == PRIMARY ?
task.execution_time :
task.sync_time);
return time +
ceil (R_ / task.period) *
exec_time;
}
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