Programming Assignment 2 Pthreads Solution

Assignment







Using your implementation of a model scientific computing problem from programming assignment 1, investigate thread-ing this application with posix threads.







Part One - Disposable Threads







Implement a pthread parallel version of your sequential program using a disposable threads model which meets the following requirements:




create / destroy your threads within the convergence loop, creating new threads for each loop iteration. implement the number of threads as the third program parameter.

Your program should now execute similar to: disposable <affect_rate <epsilon <num_threads < infile




Name this program: <lastname_<firstname_disposable.c (for example: jones_jeffrey_disposable.c).




In other respects, conform to the requirements for assignment 1.







Part Two - Persistent Threads







Implement a pthread parallel version of your sequential program using a persistent threads model which meets the following requirements:




Move thread creation outside of the convergence loop, and add a barrier or barriers as necessary within your program to properly synchronize the threads.




Destroy all threads only one time.




Name this program: <lastname_<firstname_persistent.c (for example: jones_jeffrey_persistent.c).




Your program should now execute similar to: persistent <affect_rate <epsilon <num_threads < infile




In other respects, conform to the requirements for part one above.










Testing and Submission Instructions




Provide a single make file which will build both program versions, naming the executables "disposable" and "persistent", as appropriate. Your makefile should execute with the command "make," with no parameters.




Compile your programs, as with assignment 1, with optimizer level3 (-O3) and (-lrt) <small LRT option. (Note: the -pthread option may be used in lieu of or in addition to -lrt on some systems.)







The Ohio State University
CSE 5441 – Dr. J. S. Jones Autumn 2017







Instrument your programs as with assignment 1.




Collect timing results for both versions of your program using 2, 8, 16, and 32 threads and test input file test-grid_400_12206, using the values for epsilon and affect _rate you developed in lab 1.




All timing tests should be done on the stdlinux accounts. Use the “top” command to help select a time when system use is low.




Other than execution times, your parallel program should achieve the same results (final convergence values, number of iterations required) as your serial program.




Ensure the program can be compiled with "make", before submitting. Create a directory "cse5441_lab2". Within this directory, place:

– all program files (.c or .cc files);




– makefile




– report in .pdf format






If you are in 12:45 section use command: "submit
c5441aa
lab2
cse5441_lab2"
to submit


If you are in 2:20 section use command: "submit
c5441ab
lab2
cse5441_lab2"
to submit



do not include other files (executables, etc), and do not create any sub-directories. Ensure that your submission files all have group read permissions.




Report Requirements




Present your program output and timing results for the testgrid_400_12206 test file from your sequential program as well as both versions of your pthreads parallel program (for all requested numbers of threads).




Summarize timing results, being sure to answer the following questions (at a minimum).




– Did this program perform better sequentially or in parallel?




– Which number of threads was most effective?




– Which parallel version (disposable or persistent) was most effective?




– How did your results match or conflict with your expectations?




– Were there any unexpected anomalies in the timing information collected?




– Which timing methods seem best for parallel programs? How does this compare with your expectations?




If your parallel program produces results which differ from your serial version, point this out and explain. Submit all reports in .pdf format.




















































The Ohio State University