Add hook microbenchmark.

Makefile.in

@@ -242,7 +242,9 @@ else
 CPP_SRCS :=
 TESTS_INTEGRATION_CPP :=
 endif
-TESTS_STRESS := $(srcroot)test/stress/microbench.c
+TESTS_STRESS := $(srcroot)test/stress/microbench.c \
+	$(srcroot)test/stress/hookbench.c
+
 
 TESTS := $(TESTS_UNIT) $(TESTS_INTEGRATION) $(TESTS_INTEGRATION_CPP) $(TESTS_STRESS)
 

test/stress/hookbench.c

@@ -0,0 +1,73 @@
+#include "test/jemalloc_test.h"
+
+static void
+noop_alloc_hook(void *extra, hook_alloc_t type, void *result,
+    uintptr_t result_raw, uintptr_t args_raw[3]) {
+}
+
+static void
+noop_dalloc_hook(void *extra, hook_dalloc_t type, void *address,
+    uintptr_t args_raw[3]) {
+}
+
+static void
+noop_expand_hook(void *extra, hook_expand_t type, void *address,
+    size_t old_usize, size_t new_usize, uintptr_t result_raw,
+    uintptr_t args_raw[4]) {
+}
+
+static void
+malloc_free_loop(int iters) {
+	for (int i = 0; i < iters; i++) {
+		void *p = mallocx(1, 0);
+		free(p);
+	}
+}
+
+static void
+test_hooked(int iters) {
+	hooks_t hooks = {&noop_alloc_hook, &noop_dalloc_hook, &noop_expand_hook,
+		NULL};
+
+	int err;
+	void *handles[HOOK_MAX];
+	size_t sz = sizeof(handles[0]);
+
+	for (int i = 0; i < HOOK_MAX; i++) {
+		err = mallctl("experimental.hooks.install", &handles[i],
+		    &sz, &hooks, sizeof(hooks));
+		assert(err == 0);
+
+		timedelta_t timer;
+		timer_start(&timer);
+		malloc_free_loop(iters);
+		timer_stop(&timer);
+		malloc_printf("With %d hook%s: %"FMTu64"us\n", i + 1,
+		    i + 1 == 1 ? "" : "s", timer_usec(&timer));
+	}
+	for (int i = 0; i < HOOK_MAX; i++) {
+		err = mallctl("experimental.hooks.remove", NULL, NULL,
+		    &handles[i], sizeof(handles[i]));
+		assert(err == 0);
+	}
+}
+
+static void
+test_unhooked(int iters) {
+	timedelta_t timer;
+	timer_start(&timer);
+	malloc_free_loop(iters);
+	timer_stop(&timer);
+
+	malloc_printf("Without hooks: %"FMTu64"us\n", timer_usec(&timer));
+}
+
+int
+main(void) {
+	/* Initialize */
+	free(mallocx(1, 0));
+	int iters = 10 * 1000 * 1000;
+	malloc_printf("Benchmarking hooks with %d iterations:\n", iters);
+	test_hooked(iters);
+	test_unhooked(iters);
+}