Pintos Project1: Threads

The functionality of the given minimally functional thread system is extended, with regard to the synchronization problems.

Implements

1. Alarm Clock

Reimplement timer_sleep(), defined in devices/timer.c. Although a working implementation is provided, it "busy waits," that is, it spins in a loop checking the current time and calling thread_yield() until enough time has gone by. Implement it to avoid busy waiting.

Function

void timer_sleep (int64_t ticks)

2. Priority Scheduling

Implement priority scheduling in Pintos. When a thread is added to the ready list that has a higher priority than the currently running thread, the current thread should immediately yield the processor to the new thread. Similarly, when threads are waiting for a lock, semaphore, or condition variable, the highest priority waiting thread should be awakened first. A thread may raise or lower its own priority at any time.

Function

void thread_set_priority (int new_priority)

int thread_get_priority (void)

3. Advanced Scheduler

Implement a multilevel feedback queue scheduler similar to the BSD scheduler to reduce the average response time for running jobs on your system.

Build

First, cd into the threads directory. Then, issue the make command. This will create a build directory under threads, populate it with a Makefile and a few subdirectories, and then build the kernel inside.

./src/threads/make

Testing

A script scores the output as "pass" or "fail" and writes the verdict to t.result.

./src/threads/make check

Result

Tests: 27/27 pass

Reference

Provide the Pintos Gudie👍

whaleeej/Pintos-1