[Operating System] {ud923} P3L4: Synchronization Constructs

Posted 2021-12-06 ecoflex

 

 

• Anderson, Thomas E.
  "The Performance of Spin Lock Alternatives for Shared-Memory Multiprocessors".
  IEEE Transactions on Parallel and Distributed Systems, Vol. 1, No. 1, January 1990.

 

 

 

 Visual Metaphor

 

 

 

 

 

 

More About Synchronization 

 

in order to guarantee the correctness of the sync => via atomic instructions

 

 

 

 Spinlocks

 

 

with mutexes, the thread would have relinquished the CPU and allowed for another thread to run.

 With spinlocks, the thread will spin. It will burn CPU cycles until the lock becomes free or until the thread gets preempted for some reason. eg. spinining until ultimately its time slice expired or potentially a higher priority thread became runable.

 

 

 

Semaphores 

 

 

 

 

 

Toggle Sidebar POSIX Semaphores 

 

 

 

 

 Quiz Help

If you need help, then use a sem_init() man page reference. https://linux.die.net/man/3/sem_init

 

A mutex is sometimes refered to as a binary semaphore in which it can either be "locked" or "free" -- this affects argument 2

 

 

 Reader Writer Locks

 

 RW locks => reader writer locks => similar to mutex => need to specify the type (R or W)

 

 

 

 Using Reader Writer Locks

 

 

 Monitors

 

 

 

 More Synchronization Constructs

 

 

 

 

 Sync Building Block Spinlock

 

We must have some support from the hardware in order to make sure that some of this checking of lock value

 

 

 

 https://blog.csdn.net/qq_21792169/article/details/50822702

 

 

 

 

Need for Hardware Support 

 

 

 

Atomic Instructions 

 

 

 

 

 

 Shared Memory Multiprocessors

 

 

 

 

 Cache Coherence

 

 

 

Cache Coherence and Atomics 

 

 

 

 Spinlock Performance Metrics

 

 

 

 

Test and Set Spinlock 

 

 

 

 

 

 Test and Set Spinlock

 

 

 

 

 

Spinlock “Delay” Alternatives 

 

 

 

Picking a Delay 

 

 

 

 

Queueing Lock 

 

 

 

 

 Queueing Lock Implementation

 

 

 

 

 Spinlock Performance Comparisons