Index: uspace/app/hbench/Makefile
===================================================================
--- uspace/app/hbench/Makefile	(revision ebb0835c2c47eb2e0f1fd4e27708490ece3c25db)
+++ uspace/app/hbench/Makefile	(revision c2db02a84b47571f052e5f35b690ec6d1b814ad3)
@@ -43,5 +43,6 @@
 	ipc/ping_pong.c \
 	malloc/malloc1.c \
-	malloc/malloc2.c
+	malloc/malloc2.c \
+	synch/fibril_mutex.c
 
 include $(USPACE_PREFIX)/Makefile.common
Index: uspace/app/hbench/benchlist.c
===================================================================
--- uspace/app/hbench/benchlist.c	(revision ebb0835c2c47eb2e0f1fd4e27708490ece3c25db)
+++ uspace/app/hbench/benchlist.c	(revision c2db02a84b47571f052e5f35b690ec6d1b814ad3)
@@ -40,4 +40,5 @@
 benchmark_t *benchmarks[] = {
 	&benchmark_dir_read,
+	&benchmark_fibril_mutex,
 	&benchmark_file_read,
 	&benchmark_malloc1,
Index: uspace/app/hbench/hbench.h
===================================================================
--- uspace/app/hbench/hbench.h	(revision ebb0835c2c47eb2e0f1fd4e27708490ece3c25db)
+++ uspace/app/hbench/hbench.h	(revision c2db02a84b47571f052e5f35b690ec6d1b814ad3)
@@ -91,4 +91,5 @@
 /* Put your benchmark descriptors here (and also to benchlist.c). */
 extern benchmark_t benchmark_dir_read;
+extern benchmark_t benchmark_fibril_mutex;
 extern benchmark_t benchmark_file_read;
 extern benchmark_t benchmark_malloc1;
Index: uspace/app/hbench/synch/fibril_mutex.c
===================================================================
--- uspace/app/hbench/synch/fibril_mutex.c	(revision c2db02a84b47571f052e5f35b690ec6d1b814ad3)
+++ uspace/app/hbench/synch/fibril_mutex.c	(revision c2db02a84b47571f052e5f35b690ec6d1b814ad3)
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2019 Vojtech Horky
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup hbench
+ * @{
+ */
+
+#include <fibril_synch.h>
+#include <stdatomic.h>
+#include "../hbench.h"
+
+/*
+ * Simple benchmark for fibril mutexes. There are two fibrils that compete
+ * over the same mutex as that is the simplest scenario.
+ */
+
+typedef struct {
+	fibril_mutex_t mutex;
+	uint64_t counter;
+	atomic_bool done;
+} shared_t;
+
+static errno_t competitor(void *arg)
+{
+	shared_t *shared = arg;
+	fibril_detach(fibril_get_id());
+
+	while (true) {
+		fibril_mutex_lock(&shared->mutex);
+		uint64_t local = shared->counter;
+		fibril_mutex_unlock(&shared->mutex);
+		if (local == 0) {
+			break;
+		}
+	}
+
+	atomic_store(&shared->done, true);
+
+	return EOK;
+}
+
+static bool runner(benchmeter_t *meter, uint64_t size,
+    char *error, size_t error_size)
+{
+	shared_t shared;
+	fibril_mutex_initialize(&shared.mutex);
+	shared.counter = size;
+	atomic_store(&shared.done, false);
+
+	fid_t other = fibril_create(competitor, &shared);
+	fibril_add_ready(other);
+
+	benchmeter_start(meter);
+	for (uint64_t i = 0; i < size; i++) {
+		fibril_mutex_lock(&shared.mutex);
+		shared.counter--;
+		fibril_mutex_unlock(&shared.mutex);
+	}
+	benchmeter_stop(meter);
+
+	while (!atomic_load(&shared.done)) {
+		fibril_yield();
+	}
+
+	return true;
+}
+
+benchmark_t benchmark_fibril_mutex = {
+	.name = "fibril_mutex",
+	.desc = "Speed of mutex lock/unlock operations",
+	.entry = &runner,
+	.setup = NULL,
+	.teardown = NULL
+};
+
+/** @}
+ */