spinlock.h File Reference

High-performance reader-writer spinlock implementation. More...

#include <stdatomic.h>

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Classes
struct	fast_rwlock_t
	Reader-writer spinlock structure. More...

Detailed Description

High-performance reader-writer spinlock implementation.

This header provides a custom RW-spinlock optimized for short critical sections and high-concurrency scenarios. It significantly outperforms pthread_rwlock_t when lock hold times are very brief (microseconds) due to lower overhead.

The spinlock uses a single atomic integer to track state:

• state >= 1: Number of active readers
• state == 0: Unlocked
• state == -1: Write lock held

Warning

This spinlock busy-waits (spins) when contended. Use only for:

• Very short critical sections (< 100 microseconds)
• Low to moderate contention scenarios
• Systems where context switching overhead exceeds spin cost

For longer critical sections or high contention, use pthread_rwlock_t instead.

Note

Thread-safe: All operations are atomic and safe for concurrent use.

Not reentrant: A thread cannot acquire the same lock recursively.

Definition in file spinlock.h.