About

In this project we explore basic Multi-threading in C.

Once the program starts:

• multiple Worker threads are created, the main thread will be the Dispatcher which will read Jobs and store them in a Queue. the Queue is accessible to the worker threads. Each Worker thread reads a job from the queue and executes it.

• Multiple counters will be created in the form of files. the workers' job is to manipulate those counters according to the jobs list.

• Mutex is used to protect the counters from being overwritten by multiple threads

• conditional variables are used to wake up sleeping Worker threads.

for example: given the following jobs list:

worker;repeat 1;increment 5 ;decrement 6 ;msleep 1000
worker;repeat 1;increment 5 ;decrement 6 ;msleep 1000
dispatcher_msleep 1000;
worker;increment 5;;msleep 1000

• the dispatcher inserts the first two jobs into the Queue, goes to sleep for 1 second and inserts the last job to the queue.

• as soon as the queue is not empty a worker will read the first job: increment the counter 5 (file #5) and decrement the counter 6 (file #6) and go to sleep for 1 second

• another worker will read the second line and do the same

• lastly a worker will increment the counter 5 and go to sleep for 1 second.

Summary

• Dispatcher inserts jobs into a queue serially.

• In the background, worker threads read from the queue and executes the pending jobs.

How to run the code ?

note:

• Maximum threads number is 4096
• Maximum counters number is 100

run the following commands:

1. make

2. worker_dispatcher <command file> <#Threads> <#Counters> <log enabled>

for example, if we want 5 worker threads, 10 counters, threads log files, and the commands are specified in test.txt:

2. worker_dispatcher test.txt 5 10 1

Without threads log files:

2. worker_dispatcher test.txt 5 10 0

to clean up after the program finishes running:

3. make clean