From de9eb7df1a47730d60819733506f794a7a467ffb Mon Sep 17 00:00:00 2001
From: jeff <jpm8766@rit.edu>
Date: Fri, 22 Mar 2013 11:14:28 -0400
Subject: [PATCH] Modified to fix EDF; if tasks miss too many deadlines during
 normal operation, the program kills itself to prevent it from spiraling out
 of control.

---
 EDFScheduler.cpp        |  2 +-
 SchedulingAlgorithms.cc | 11 +++++++++--
 Task.cpp                | 13 ++++++++++++-
 Task.h                  |  4 +++-
 TestSets/Test6          |  2 +-
 Thread.h                | 10 +++++-----
 6 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/EDFScheduler.cpp b/EDFScheduler.cpp
index 77134e3..183f43c 100755
--- a/EDFScheduler.cpp
+++ b/EDFScheduler.cpp
@@ -23,7 +23,7 @@ void EDFScheduler::scheduleTasks() {
 		Task *task = taskSet[i];
 
 		//if this task is running, set it back to ready
-		if(task->getPriority() <= TP_RUNNING) {
+		if(task->getPriority() != TP_READY) {
 			task->setPriority(TP_READY);
 		}
 
diff --git a/SchedulingAlgorithms.cc b/SchedulingAlgorithms.cc
index c3393d0..5738ab5 100755
--- a/SchedulingAlgorithms.cc
+++ b/SchedulingAlgorithms.cc
@@ -2,6 +2,7 @@
 #include <iostream>
 #include <fstream>
 #include <string>
+#include <unistd.h>
 using namespace std;
 
 #include "SchedulingAlgorithms.h"
@@ -55,12 +56,18 @@ int main(int argc, char *argv[]) {
 
 		//start the simulation
 		sc->start();
-		sc->join();					//this will stick because the thread never gets stop()'d
 
-		cout << "Exiting..." << endl;
+//		usleep(100000);
+
+//		sc->stop();
+		sc->join();					//this will stick because the thread never gets stop()'d
 
 		//cleanup
 		delete sc;
+
+		cout << "Exiting..." << endl;
+
+
 	} else {
 		cerr << "Usage: " << argv[0] << " Filename SchedulerInt" << endl;
 	}
diff --git a/Task.cpp b/Task.cpp
index bbfd985..5679818 100755
--- a/Task.cpp
+++ b/Task.cpp
@@ -8,6 +8,7 @@
 #include "Task.h"
 #include <cassert>
 #include <semaphore.h>
+#include <stdlib.h>
 
 //1ms deadline and period
 #define TIMER_PERIOD_NANO	(5000000)
@@ -45,6 +46,7 @@ scheduler(scheduler) {
 }
 
 Task::~Task() {
+	pthread_abort(thread);
 	sem_destroy(&doWork);
 	timer_delete(deadlineTimer);
 }
@@ -117,7 +119,7 @@ void Task::setComputeTime(int c) {
 
 long Task::getRemainingDeadline() {
 	timer_gettime(deadlineTimer, &deadlineRemainingSpec);
-	return deadlineRemainingSpec.it_value.tv_nsec;
+	return (deadlineRemainingSpec.it_value.tv_nsec + 2500000)/50000000;
 }
 
 int Task::getPeriod() {
@@ -136,6 +138,7 @@ void Task::setDeadline(int d) {
 	deadline = d;
 }
 
+static int missedDeadlines = 0;
 void Task::tick(union sigval sig) {
 	//get the schedulers semaphore from the timer...
 	Task* self = (Task*) sig.sival_ptr;
@@ -149,6 +152,14 @@ void Task::tick(union sigval sig) {
 #if TRACE_EVENT_LOG_CRITICAL
 		TraceEvent(_NTO_TRACE_INSERTUSRSTREVENT, TRACE_EVENT_DEADLINE_MISS, self->deadlineMissedMsg);
 #endif
+		missedDeadlines++;
+
+		if(missedDeadlines > MAX_DEADLINE_MISSES) {
+			exit(-1);
+		}
+	} else {
+		if((missedDeadlines > 0))
+			missedDeadlines--;
 	}
 
 	self->state = TP_READY;
diff --git a/Task.h b/Task.h
index f5f7594..be2c4a7 100755
--- a/Task.h
+++ b/Task.h
@@ -17,8 +17,10 @@
 #include "Thread.h"
 #include "SchedulingAlgorithms.h"
 
+#define MAX_DEADLINE_MISSES (15)
+
 enum TaskPriority {
-	TP_FINISHED = 1, TP_READY = 37, TP_RUNNING = 38, TP_SCHEDULER = 39
+	TP_FINISHED = 1, TP_READY = 7, TP_RUNNING = 8, TP_SCHEDULER = 9
 };
 
 class Task : public Thread {
diff --git a/TestSets/Test6 b/TestSets/Test6
index 55306a6..d540e3b 100644
--- a/TestSets/Test6
+++ b/TestSets/Test6
@@ -1,2 +1,2 @@
 T1 3 4 4
-T2 2 8 8
+T2 3 8 8
diff --git a/Thread.h b/Thread.h
index 8e15ab8..2108c6c 100755
--- a/Thread.h
+++ b/Thread.h
@@ -68,16 +68,16 @@ class Thread {
 	 */
 	std::string name;
 
-private:
 	/**
-	 * Static function which calls the Thread's run() method.
+	 * pthread id for this thread.
 	 */
-	static void* pthread_entry(void* args);
+	pthread_t thread;
 
+private:
 	/**
-	 * pthread id for this thread.
+	 * Static function which calls the Thread's run() method.
 	 */
-	pthread_t thread;
+	static void* pthread_entry(void* args);
 };
 
 #endif /* THREAD_H_ */