Bounded waiting

Question

How to check for bounded waiting???will there be deadlock??...I know in this code mutual exclusion is satisfied but progress is not satisfied!!!
Consider the following code:-
i = 0, j = 1 and initially both flags are false.
do { flag[i] = true;
while(flag[j]);
Critical Section
flag[i] = false;
remainder section
} while(1);

Answer 1

Deadlock is possible... When flag[I]= true and flag[j] = true..

Process 0: Make flag[I] =true and than preempted now process 1: enter and make flag[j] = true ..

So no one enter into critical section...

Bounded waiting : when only single process gets the turn to enter into critical section every time even other process are also interested with critical section..

So there should be bound on no.of time particular process can enter into critical section...

Comments

Er Gabbar: here bounded waiting is not satisfied implies there is a deadlock????

In any code if bounded waiting is not satisfied means there is a deadlock???

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No...

Bounded waiting not satisfied means one process is continuously entering into cs and don't give chance to other process...

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My question is in the above code , bounded waiting is satisfied or not???

M I correct progress is not satisfied???

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Hi @papesh, In the cade given i don't see any statement where flag[j] will be assigned true. and it is in while condition and it is initialized with false value, then i think that while condition is not doing anything.

And there is no condition checking on flag[i] to enter CS also. So i think there will be no deadlock and also there will be no mutual exclusion. Progress will not be stopped and bounded waiting is also possible. Please clarify.

Answer 2

from my point of view neither progress not bounded waiting is satisfied

Progress: If no process is executing in its critical section and some processes wish to enter their critical sections, then only those processes that are not executing in their remainder section can participate in deciding which will enter its critical section next, and this selection cannot be postponed indefinitely.

Bounded waiting: There exists a bound, or limit, on the number of times other processes are allowed to enter their critical sections after a process has made request to enter its critical section and before that request is granted.

so here the supposs p0 and p1 make there flag = true, both of the process wish to enter the critical section but non of them will enter  and also bounded waiting is not satified as you can see in the code

Comments

Bounded waiting is not satisfied as P0 or P2 can enter the CS recursively. I mean P0 can continuously enter the CS and P1 may not get chance. So, there is no bound on waiting. Hence, its not Bounded Waiting. Please let me know if I am correct or not.