Races can either be set to end at a certain number of laps, or be set to run for a certain length of time, as seen in endurance racing. It supports output to 2D and 3D including virtual reality goggles like Oculus Rift. (d) The variable process_left is made private instead of shared.LFS features input support for steering wheels, mice, keyboards, joysticks, and gamepads. (c) Context switch is disabled at the beginning of the barrier and re-enabled at the end. (b) At the beginning of the barrier the first process to enter the barrier waits until process_arrived becomes zero before proceeding to execute P(S). (a) Lines 6 to 10 are simply replaced by process_arrived.
Which one of the following rectifies the problem in the implementation? All process have reached the barrier but since the process_arrived=2, all processes keeps on waiting. P3 invokes the barrier function, hence process_arrived=2.
At this stage assume that P2 invokes the barrier function, hence process_arrived=1 and it waits. "If" condition is true and now process_arrived and process_left is reset to 0. Now P3 leaves the barrier which makes process_left=3. Soon P2 leaves the barrier, which makes process_left=2. Now assume that P1 again invokes the barrier function immediately. Now assume that P1 continues its execution and leaves the barrier and makes process_left=1. Every process arrives at the barrier, that is it completes its first section of the code. It is mentioned that there are 3 processes. (d) The barrier implementation is correct if there are only two processes instead of three. (c) Lines 6 to 10 need not be inside a critical section (b) The barrier implementation may lead to a deadlock if two barrier in invocations are used in immediate succession. (a) The barrier implementation is wrong due to the use of binary semaphore S The above implementation of barrier is incorrect. In a concurrent program all the three processes call the barrier function when they need to synchronize globally.ġ1. The variables process_arrived and process_left are shared among all processes and are initialized to zero. Consider the following C implementation of a barrier with line numbers shown on left. Let the number of processes in the set be three and S be a binary semaphore with the usual P and V functions. each process in the set arrives at the barrier and waits for all others to arrive and then all processes leave the barrier. Linked Answer Questions for 11 & 12 Barrier is a synchronization construct where a set of processes synchronizes globally i.e.
0 kommentar(er)
