This repository contains a collection of spinlock implementations with various optimizations. This includes a basic (naive) spinlock, and ones with the following optimizations:
- Spinning locally
- Addresses constant contention from writes
- Spinning with active backoff (
forloop)- Addresses bursty contention when the lock is released
- Spinning with passive backoff (
_mm_pause()intrinsic)- Addresses bursty contention with the lock is released and saves on power
- Spinning with exponential backoff
- Addresses bursty contention and power while accounting for non-uniform wait times of threads
- Spinning with randomized backoff
- Addresses bursty contention and power while accounting for non-uniform wait times of threads
- Ticket-based spinlock
- Addresses unfairness from previous implementations
The benchmark used to evaluate the performance (among other metrics) of our spinlock is a simple loop where each thread increments a shared variable after grabbing the lock. This provides an extreme high-contention (but simple) scenario where we can evaluate out lock.
We also have benchmarks for the pthread_mutex_t, and pthread_spinlock_t, to compare performance and assembly against state-of-the-art locking mechanisms.