A repository containing a set of custom tools I wrote to help debug Project 4 (multi-threaded scheduling simulation) of Georgia Tech's CS 2200 Systems and Networks in Spring 2024. Due to Academic Integrity Policies, the rest of the project code is not included.

In student.h, include debug.h.

Then, near the top of your student.c, make sure to have this block of code:

#ifndef DEBUG_H
    #define debug_init(lvl, num_mutexes, ...)
    #define debug_destroy()
    #define debug1(type, p)
    #define debug2(type, p)
    #define debug3(type, p)
    #define mutex_lock(mutex)      pthread_mutex_lock(mutex)
    #define mutex_unlock(mutex)    pthread_mutex_unlock(mutex)
    #define cond_wait(cond, mutex) pthread_cond_wait(cond, mutex)
    #define cond_signal(cond)      pthread_cond_signal(cond)
    #define cond_broadcast(cond)   pthread_cond_broadcast(cond)
#endif

This will prevent errors when submitting to GradeScope.
Next, call debug_init() in main with the following parameters:

• level: The debug level (1-3) (0 is off)
• age_weight: A pointer to the age_weight variable
• count: The number of pointers you want to map to names
• pointers: A list of pointers to map to names
• names: A list of names to map to pointers

The recommended way to do this is as follows:

First, immediately after the includes, have

int DBGLVL =  3;

The value of DBGLVL will be the debug level. Having it at the top will allow you to easily change the debug level.

Then, as the first line of main(), have

debug_init(DBGLVL, &age_weight, 3, &current_mutex, "current_mutex",
    &queue_mutex, "queue_mutex", &queue_not_empty, "queue_not_empty");

After calling debug_init(), you can use the following functions:

debug1(char  type, void*  p) // Print a debug message at level 1
debug2(char  type, void*  p) // Print a debug message at level 2
debug3(char  type, void*  p) // Print a debug message at level 3
mutex_lock(&mutex)           // Lock a mutex with debug messages
mutex_unlock(&mutex)         // Unlock a mutex with debug messages
cond_wait(&cond, &mutex)     // Wait on a cond variable with debug messages
cond_signal(&cond)           // Signal a condition variable
cond_broadcast(&cond)        // Broadcast a cond variable with debugging

The 'type' parameter in the debug functions is a character that specifies the type of the 'p' parameter.

The following are provided for users:

• 'd': Print a data string
• 'i': Print an integer
• 'p': Print a process name
• 'p': Print a process (pcb_t)
• 'q': Print a queue
• 'Q': Print a queue in detail

The other types of debug messages are called via other functions in the debugger. Feel free to use them but realistically you should be using the other provided functions, which invoke these internally.

• 'l': Indicate waiting for a mutex to lock
• 'm': Indicate a mutex has been locked
• 'u': Indicate unlocking a mutex
• 'w': Indicate waiting on a cond variable
• 's': Indicate signaling a cond variable
• 'b': Indicate broadcasting a cond variable
• 'c': Indicate a cond variable has been signaled

For more information, read the following examples of using the debugger or read the comments in debug.h.

The DBGLVL indicates the verbosity of the debug output. Level 3 is used by the pthread wrapper functions. It is recommended to use level 2 to indicate calling of functions, and level 1 to help with targeting specific issues.

It can be useful to print the process when context switching, or print the cpu_id that a function is called with.

For more information about how to use debug.h, read the comments in the file itself. Implementation is in debug.c.

An autograder was provided via GradeScope. However, this solution ran slowly, and would give often useless errors. Thus, I created local-autograder.py.

Depends on python 3. Should be placed in the same directory as the compiled os-sim binary, or you can modify the BIN variable to include a path to the binary.

Run using the command python3 local-autograder.py. It will generate a directory called output, which contains logs of each run, and write the stats to both stdout and a file called stats.txt.