Description
Project Requirements
• Build a Rate Monotonic Scheduler with four threads
• Scheduler details:
• Threads T1 through T4
• Thread T1 has a period of 1 unit
• Thread T2 has a period of 2 units
• Thread T3 has a period of 4 units
• Thread T4 has a period of 16 units
• A unit shall be anywhere from 10-100 ms (depending on operating
system options)
• Each thread will execute the same doWork method but run it a
different amount of times:
• Thread T1 executes doWork 1 time
• Thread T2 executes doWork 2 times
• Thread T3 executes doWork 4 times
• Thread T4 executes doWork 16 times
3 CPSC 380 PROJECT 3
Project Requirements
• Scheduler shall have a major frame period of 16 units of
time
• Program shall start scheduler and four threads that are to
be scheduled
• Scheduler needs to be woken up by a periodic source
(signal/timer/etc) and it shall schedule the threads
• The program shall run for 10 periods and then terminate, but not
before printing out how many times each thread ran
• Each thread shall increment a dedicated counter each
time it runs
• The scheduler shall be able to identify if a thread has
missed its deadline and keep track of how many times it
happens
CPSC 380 PROJECT 3
Project Requirements
• The following test cases shall be demonstrated
• Nominal case with no overruns
• Failed case where the doWork function is called as many times as
required to lead to an overrun condition in T2 – what happens to
other threads?
• Failed case where T3 has an overrun condition – what happens to
other threads?
• All results are printed out at the completion of the run to not effect
the timing
• When an overrun condition occurs, the scheduler shall still
schedule the thread and not skip a period
Project Requirements
• doWork function will do the following:
• Will multiply the content of each cell of a 10×10 matrix starting with column 0 followed by 5, then
1 followed by 6, etc
6 CPSC 380 PROJECT 3
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 3 5 7 9 2 4 6 8 10
Traverse and multiply
in this direction
Column order
of execution
Hints
• Remember that you have a scheduler that is orchestrating
everything else – separate thread
• Priorities are essential – remember rules of RMS
• Semaphores needed for synchronization
• May need mutex to protect shared data between scheduler and
threads – remember priority inversion
• You need to use processor affinity on all your threads (including
the scheduler)
• For the overrun conditions, you should keep scheduling the
thread that has missed its deadline even after it is in an overrun
condition
• Do not skip scheduling for that execution period
• You can initially use a sleep( ) or similar function to set the
timing on your scheduler until you work out the synchronization
with the other threads and then replace with a timer
Project Artifacts
• Demonstrate by outputting the counters for each thread
that shows how many times each one ran and how many
times an overrun occurred per thread
• Can be printed to the screen or sent to a file
• Students must turn in the following:
• Source code
• Executable
• Output of the program
• A brief design description that explains the design, how were the
threads synchronized and dispatched
Operating System Concepts – 9th Edition Silberschatz, Galvin and Gagne ©2013
CPSC 380 PROJECT 3
