Question

作为我的任务，我必须验证Dekker的算法 - 但有3个过程 -

我只能找到2个进程的原始版本。

目标不是算法，而是SMV系统中的实现和验证 http://www.cs.cmu.edu/~modelcheck/smv.html

Answer 1

您可能应该问课程人员，但您可以使用两个Dekker互斥锁来实现三进程互斥锁。进程0和1竞争获取互斥锁A;互斥锁A和进程2的持有者竞争获取互斥锁B，允许其持有者运行关键部分。

Answer 2

  // Dekkers algorithm version3
  system:
  boolean t1WantsToEnter=false;
  boolean t2WantsToEnter=false;
  startThreads;//initialize and launch all threads

  Thread T1;
  void main();{
  while(!done);
  {
  t1WantsToEnter=true;
  while(t2WantsToEnter); //wait
  //critical section cokde
  t1WantsToEnter=false;
  //code outside critical section

  Thread T2;
  void main();{
  while(!done);
  {
  t2WantsToEnter=true;
  while(t1WantsToEter);//wait
  //critical section code
  t2WantsToEnter=false;
  //code outside critical section
  // if u want to know how this code is executed using RAM diagram,

Answer 3

// Dekkers algorithm version3
  system:
  boolean t1WantsToEnter=false;
  boolean t2WantsToEnter=false;
  startThreads;//initialize and launch all threads

  Thread T1;
  void main();{
  while(!done);
  {
  t1WantsToEnter=true;
  while(t2WantsToEnter); //wait
  //critical section cokde
  t1WantsToEnter=false;
  //code outside critical section
  } //end outer while
  } //end Thread T1
  Thread T2;
  void main();{
  while(!done);
  {
  t2WantsToEnter=true;
  while(t1WantsToEter);//wait
  //critical section code
  t2WantsToEnter=false;
  //code outside critical section
  } //end outer while
  } //end Thread T2

Dekker的3个过程的算法

3 个答案: