Merge pull request #84 from jty2/github-jty2.swap_mutex.use_store_release

jty2 · web-flow · commit 8b271c966828 · 2025-05-06T12:34:21.000-05:00
swap_mutex: use store release in lock_release() For issue #81
diff --git a/benchmarks/lockhammer/tests/swap_mutex.h b/benchmarks/lockhammer/tests/swap_mutex.h
@@ -35,12 +35,12 @@ static inline unsigned long lock_acquire (uint64_t *lock, unsigned long threadnu
 	unsigned long val = 1;
 
 	while (val) {
-		val = swap64 (lock, 1);
+		val = swap64 (lock, 1); // uses acquire-release semantics
 	}
 
 	return 0;
 }
 
 static inline void lock_release (uint64_t *lock, unsigned long threadnum) {
-	*(volatile unsigned long *) lock = 0;
+	__atomic_store_n(lock, 0, __ATOMIC_RELEASE);
 }

Original file line number	Diff line number	Diff line change
`@@ -35,12 +35,12 @@ static inline unsigned long lock_acquire (uint64_t *lock, unsigned long threadnu`
`35`	`35`	`unsigned long val = 1;`
`36`	`36`
`37`	`37`	`while (val) {`
`38`		`- val = swap64 (lock, 1);`
	`38`	`+ val = swap64 (lock, 1); // uses acquire-release semantics`
`39`	`39`	`}`
`40`	`40`
`41`	`41`	`return 0;`
`42`	`42`	`}`
`43`	`43`
`44`	`44`	`static inline void lock_release (uint64_t *lock, unsigned long threadnum) {`
`45`		`- (volatile unsigned long ) lock = 0;`
	`45`	`+ __atomic_store_n(lock, 0, __ATOMIC_RELEASE);`
`46`	`46`	`}`