diff --git a/include/haproxy/thread.h b/include/haproxy/thread.h
index 969e7dc13..d9c280da9 100644
--- a/include/haproxy/thread.h
+++ b/include/haproxy/thread.h
@@ -59,7 +59,6 @@ enum { all_threads_mask = 1UL };
 enum { all_tgroups_mask = 1UL };
 enum { threads_harmless_mask = 0 };
 enum { threads_idle_mask = 0 };
-enum { threads_sync_mask = 0 };
 enum { threads_want_rdv_mask = 0 };
 enum { tid_bit = 1UL };
 enum { tid = 0 };
@@ -136,10 +135,6 @@ static inline void thread_release()
 {
 }
 
-static inline void thread_sync_release()
-{
-}
-
 static inline unsigned long thread_isolated()
 {
 	return 1;
@@ -172,7 +167,6 @@ void thread_harmless_till_end(void);
 void thread_isolate(void);
 void thread_isolate_full(void);
 void thread_release(void);
-void thread_sync_release(void);
 void ha_spin_init(HA_SPINLOCK_T *l);
 void ha_rwlock_init(HA_RWLOCK_T *l);
 void setup_extra_threads(void *(*handler)(void *));
@@ -184,21 +178,16 @@ extern volatile unsigned long all_threads_mask;
 extern volatile unsigned long all_tgroups_mask;
 extern volatile unsigned long threads_harmless_mask;
 extern volatile unsigned long threads_idle_mask;
-extern volatile unsigned long threads_sync_mask;
 extern volatile unsigned long threads_want_rdv_mask;
 extern THREAD_LOCAL unsigned long tid_bit; /* The bit corresponding to the thread id */
 extern THREAD_LOCAL unsigned int tid;      /* The thread id */
 extern THREAD_LOCAL unsigned int tgid;     /* The thread group id (starts at 1) */
 
-/* explanation for threads_want_rdv_mask, threads_harmless_mask, and
- * threads_sync_mask :
+/* explanation for threads_want_rdv_mask, and threads_harmless_mask:
  * - threads_want_rdv_mask is a bit field indicating all threads that have
  *   requested a rendez-vous of other threads using thread_isolate().
  * - threads_harmless_mask is a bit field indicating all threads that are
  *   currently harmless in that they promise not to access a shared resource.
- * - threads_sync_mask is a bit field indicating that a thread waiting for
- *   others to finish wants to leave synchronized with others and as such
- *   promises to do so as well using thread_sync_release().
  *
  * For a given thread, its bits in want_rdv and harmless can be translated like
  * this :
@@ -211,9 +200,6 @@ extern THREAD_LOCAL unsigned int tgid;     /* The thread group id (starts at 1)
  *       1    |     1    | thread interested in RDV and waiting for its turn
  *       1    |     0    | thread currently working isolated from others
  *  ----------+----------+----------------------------------------------------
- *
- * thread_sync_mask only delays the leaving of threads_sync_release() to make
- * sure that each thread's harmless bit is cleared before leaving the function.
  */
 
 #define ha_sigmask(how, set, oldset)  pthread_sigmask(how, set, oldset)
diff --git a/src/thread.c b/src/thread.c
index 7d74858d7..042ad965e 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -63,7 +63,6 @@ THREAD_LOCAL struct thread_ctx *th_ctx = &ha_thread_ctx[0];
 volatile unsigned long threads_want_rdv_mask __read_mostly = 0;
 volatile unsigned long threads_harmless_mask = 0;
 volatile unsigned long threads_idle_mask = 0;
-volatile unsigned long threads_sync_mask = 0;
 volatile unsigned long all_threads_mask __read_mostly  = 1; // nbthread 1 assumed by default
 volatile unsigned long all_tgroups_mask __read_mostly  = 1; // nbtgroup 1 assumed by default
 THREAD_LOCAL unsigned int  tgid          = 1; // thread ID starts at 1
@@ -170,34 +169,6 @@ void thread_release()
 	_HA_ATOMIC_AND(&threads_want_rdv_mask, ~tid_bit);
 }
 
-/* Cancels the effect of thread_isolate() by releasing the current thread's bit
- * in threads_want_rdv_mask and by marking this thread as harmless until the
- * last worker finishes. The difference with thread_release() is that this one
- * will not leave the function before others are notified to do the same, so it
- * guarantees that the current thread will not pass through a subsequent call
- * to thread_isolate() before others finish.
- */
-void thread_sync_release()
-{
-	_HA_ATOMIC_OR(&threads_sync_mask, tid_bit);
-	__ha_barrier_atomic_store();
-	_HA_ATOMIC_AND(&threads_want_rdv_mask, ~tid_bit);
-
-	while (threads_want_rdv_mask & all_threads_mask) {
-		_HA_ATOMIC_OR(&threads_harmless_mask, tid_bit);
-		while (threads_want_rdv_mask & all_threads_mask)
-			ha_thread_relax();
-		HA_ATOMIC_AND(&threads_harmless_mask, ~tid_bit);
-	}
-
-	/* the current thread is not harmless anymore, thread_isolate()
-	 * is forced to wait till all waiters finish.
-	 */
-	_HA_ATOMIC_AND(&threads_sync_mask, ~tid_bit);
-	while (threads_sync_mask & all_threads_mask)
-		ha_thread_relax();
-}
-
 /* Sets up threads, signals and masks, and starts threads 2 and above.
  * Does nothing when threads are disabled.
  */