> I know I'm tooooo late to ask you for help....but please help me out..I > am really new to unix and dont know how to finish this assignment on > time.....proff. said he will be using MOSS to detect whether I > downloaded the code..please help me.. > > email me : [EMAIL PROTECTED] > > Assignment 1 > Processes, Inter-Process Communication, and Concurrency > Due September 13th midnight > Summary > In > this assignment, you will create two versions of a simple multi-process > game : one without and another with inter-process synchronization. You > will also measure the relative performance of the two versions of your > multi-process game. > Objectives > > * Learn how to create and terminate processes. > * Learn use of inter-process communication using shared memory, > semaphores, signals, etc. > * Learn the basic workings of CPU scheduling code in Linux. > > Part A: Multi-Process Game of Turns > > In > this part, you are asked to write a simple program that takes two > command-line arguments P and N. The main process creates P other child > processes, waits for all of them to complete, and then exits. All the > child processes form one logical ring among each other. (In rest of the > description, the term "process" refers to a "child process".) For > example, if the processes are numbered 1 to P, then > > * The next neighbor of process 1 is process 2, > * The next neighbor of process i is process i+1 for all i < P , and > * The next neighbor of process P is process 1, which completes a ring > among the processes. > > Assume > that a shared integer variable, called turn, identifies the number of > the processes whose turn it is at any instant. A second process-local > variable in each process, called me, identifies the identity of each > process (i.e. each process stores its own identity in a per-process > local variable me). A third per-process local variable, called next, > identifies the next process in the ring. > > The processes > sequentially pass the turns among each other in the logical ring. When > each process gets its turn, it increments another shared variable > called counter. The pseudo-code within each process for passing turns > might look something as follows. (Note: Replace turn and counter below > with appropriate ways of accessing data within shared memory regions). > > while(turn != me ) > /* do nothing - just busy loop*/ ; > > /* got my turn - increment counter */ > counter = counter + 1; > > /* give the turn to next process */ > turn = next; > > The program terminates when the each process has received N turns. > > In the above description, several programming details have been omitted for > you to figure out. This includes > > * Creating P child processes from main process. > * Constructing the logical ring among child processes. > o Initializing each child process's identity in the me variable. > o Initializing each child process' next neighbor in the next > variable. > * Initializing the shared memory region and the shared data values. > * Have the main process wait for child processes to complete N turns > before exiting. > > Part B: More Efficient Game of Turns > > You > might notice that the program you wrote in Part A is inefficient > because each process busy loops till the CPU scheduler kicks it out > (after its time-slice is over) and allows another process to execute > and make progress. (Does the program in Part A have a race condition? > Why or why not?) > > What we ideally want is that each process > should be given control of the CPU only when it is that process' turn. > Modify the program you wrote in Part A (using appropriate > synchronization mechanisms) such that each process gets to run (i.e., > gets control of the CPU) only when it is that process's turn, and at no > other time. > > Again, you would need to work out the programming details of how and where > to use inter-process synchronization. > Part C: Profiling the Game of Turns > > In > this part, you are asked to write user-level profiling code in order to > measure the performance of the two versions of programs you wrote in > Part A and Part B. Use a combination of gettimeofday() system call and > inter-process synchronization to measure (1) the average hand-over time > between two consecutive processes in the ring and (b) the total > execution time to complete N turns. Plot the measured values as graphs > when varying number of processes P and number of turns N. Explain the > results you obtain. > Submission Guidelines > > Thanking you, > > Ms. Vaidehi Pawar
How much do you pay? Cheers, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown -- http://mail.python.org/mailman/listinfo/python-list
