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update preemption demo to variable thread num

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This commit is contained in:
Christoph Urlacher
2022-07-16 00:58:59 +02:00
parent 24cf319b86
commit d1d3714b63
2 changed files with 18 additions and 13 deletions
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27
c_os/user/demo/PreemptiveThreadDemo.cc
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@ -2,34 +2,37 @@
void PreemptiveLoopThread::run() { void PreemptiveLoopThread::run() {
int cnt = 0; int cnt = 0;
while (true) { while (true) {
// Basic synchronization by semaphore // Basic synchronization by semaphore
sem->p(); sem->p();
kout.setpos(55, this->id); // Saving + restoring kout position doesn't help much as preemption still occurs,
kout << this->id << ": " << dec << cnt++ << endl; // only LoopThreads are synchronized, so other output will be disturbed sometimes
// kout.setpos(55, this->id);
// kout << fillw(3) << this->id << fillw(0) << ": " << dec << cnt++ << endl;
sem->v(); sem->v();
} }
} }
void PreemptiveThreadDemo::run() { void PreemptiveThreadDemo::run() {
kout << "PreemptiveThreadDemo ====================================" << endl;
kout << "Initializing Semaphore" << endl; kout << "Initializing Semaphore" << endl;
Semaphore* sem = new Semaphore(1); // Create this semaphore on the heap as this thread exits itself, Semaphore* sem = new Semaphore(1); // Create this semaphore on the heap as this thread exits itself,
// so stack allocated objects will be lost // so stack allocated objects will be lost
kout << "Allocating LoopThread A" << endl; // TODO: Threads disappear, the fewer loop the faster they vanish
Thread* cntA = new PreemptiveLoopThread(0, sem); // It seems like this happens with exactly 3 or 4 loopthreads
kout << "Allocating LoopThread B" << endl; Thread* threads[this->number_of_threads];
Thread* cntB = new PreemptiveLoopThread(1, sem); kout << "Allocating LoopThreads" << endl;
kout << "Allocating LoopThread C" << endl; for (unsigned int i = 0; i < this->number_of_threads; ++i) {
Thread* cntC = new PreemptiveLoopThread(2, sem); threads[i] = new PreemptiveLoopThread(i, sem);
}
kout << "Adding threads to ready queue" << endl; kout << "Adding threads to ready queue" << endl;
scheduler.ready(cntA); for (unsigned int i = 0; i < this->number_of_threads; ++i) {
scheduler.ready(cntB); scheduler.ready(threads[i]);
scheduler.ready(cntC); }
kout << "Exiting main thread" << endl; kout << "Exiting main thread" << endl;
scheduler.exit(); scheduler.exit();

4
c_os/user/demo/PreemptiveThreadDemo.h
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@ -24,8 +24,10 @@ class PreemptiveThreadDemo : public Thread {
private: private:
PreemptiveThreadDemo(const PreemptiveThreadDemo& copy) = delete; // Verhindere Kopieren PreemptiveThreadDemo(const PreemptiveThreadDemo& copy) = delete; // Verhindere Kopieren
unsigned int number_of_threads;
public: public:
PreemptiveThreadDemo() { PreemptiveThreadDemo(unsigned int n) : number_of_threads(n) {
kout << "Initialized PreemptiveThreadDemo" << endl; kout << "Initialized PreemptiveThreadDemo" << endl;
} }