CS Assignment

Objective:   Investigation of  processes  and the  resources  they use.    Our focus  is  on multicore  processors.    Usage  of  ps  an  top. Preparation:  We  want  to investigate  the  impact  of running CPU  and I/O  intensive  jobs on multi-core  processors.   For this  use  your  own computer and  only then  the  CS computers    If you don’t  own a computer, you can use  any other computer on campus  (running linux). Write  two small  programs  that  contain loops  and run for 5  minutes.  The  first  program, called  CPU-bound.c,  should just  perform  simple  arithmetic  calculations, e.g. a  counter.  The  second program, called  IO-bound.c,  should  perform  an I/O  operation, e.g.,  open a file, write  a  character into the  file  and close  it.  Again, this  should be  done  in a  loop  that will  terminate  after 5  minutes.   Make  sure  the  programs  really terminate  as  we  want  to avoid having endless  processes  hogging resources!   Read about  top  and  ps  and check out  what  information they provide, e.g., use  the  man pages  to see  what  options  are  available. Experiment  1:  (using your computer)   1)  Run  top  and see  what  processes  the  system  is  using.  Try to understand what  processes are  running and interpret  the  information displayed for each process, i.e. interpret  the columns. 2)  Now  start  executing  a  single  instance  of  your  CPU-bound  process  in the  background.  Recall  that  a  process  can be  executed in the  background by using the  “&”, e.g.  CPUbound  &.   Find out  how  to  start  a  process, stop it, and start  it  again, run it  in the foreground and send it  to the  background.   3)  Next  investigate  the  impact  of the  CPU-bound  program  using ps  and top.    4)  Now  start  the  IO-bound  in the  background and again check using  ps  and  top  its  impact.  At  this  point  you should have  a  single  instance  of  both  programs  executing.   What  do you notice  about  the  processes’ CPU  utilization?

5)  Repeat  the  experiments  with multiple  instances  of the  processes: 1.  Start  multiple  instances  of your  CPU-bound  program  to get  the  cores  working.    a.  What  do you notice  now  about  your  CPU-bound  processes?   b.  How many instances  of your  CPU  program  did you run and what  CPU utilization did you observe?   2.  Start  multiple  instances  of your  UI-bound  program.    a.  What  do you notice  now  about  your mix of processes?   b.  How many instances  of your  IO  program  should you  (did you)  run  and what  CPU  utilization did you observe?   6)  Once  you are  sure  you can document  your findings,  kill  the  processes.  How  do you find out  which processes  you should kill?   By now  you should have  figured out  how  to get  the  process  ID  (e.g., using top, ps)  and use  the  man pages  on the  kill  command.  IMPORTANT:  Verify that  you actually killed your programs! Experiment 2:   Do this  only  after  you  are  done  with  Experiment 1, unless  you  do not own  a  computer. Gather  the  information  from the  experiment on  the  CS  computers. Document  differences  between the  two systems, i.e.,  did you observe  any measurable differences  between the  CPU  and I/O  utilization between the  target  systems? Deliverables:  You need to turn in: 1)  All  source  code  of your programs  in  one  tar  file  (via  cscheckin).   This  means  you should used the  unix  tar  command, which will  create  the  tar file  called  Ass1.tar. This  tar file  is  what  you need  to turn in  using  cscheckin. 2)  A  hardcopy  of  1) the  assignment  sheet  as  cover page, 2)  your  source  code  and  3) the  report  that  shows  and explains  your findings, i.e. the  impact  of your executions  and how  they differ (or not) between the  two target  computers.  Make sure  you  include  screen shots  of your programs  in execution using  ps  and  top. Your documentation should  identify in  the  screen  shots  where  the  values  of interest are, e.g.,  by  highlighting, underlining.  Make  sure  you clearly identify the support  evidence!  This  report  is  the  real  delivery! 3)  AGAIN:  Use  this  assignment sheet as  the  cover-sheet for  the  hardcopy!