On Sep 10, 3:33 pm, "Daniel Fetchinson" <[EMAIL PROTECTED]> wrote: > > 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
Maybe. If I cant sleep tonite. -- http://mail.python.org/mailman/listinfo/python-list
