tests/atomic_add-bench: add -p to enable sync profiler

When used together with -m, this allows us to benchmark the
profiler's performance impact on qemu_mutex_lock.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/atomic_add-bench.c

@@ -26,6 +26,7 @@ static bool test_stop;
 static const char commands_string[] =
     " -n = number of threads\n"
     " -m = use mutexes instead of atomic increments\n"
+    " -p = enable sync profiler\n"
     " -d = duration in seconds\n"
     " -r = range (will be rounded up to pow2)";
 
@@ -143,7 +144,7 @@ static void parse_args(int argc, char *argv[])
     int c;
 
     for (;;) {
-        c = getopt(argc, argv, "hd:n:mr:");
+        c = getopt(argc, argv, "hd:n:mpr:");
         if (c < 0) {
             break;
         }
@@ -160,6 +161,9 @@ static void parse_args(int argc, char *argv[])
         case 'm':
             use_mutex = true;
             break;
+        case 'p':
+            qsp_enable();
+            break;
         case 'r':
             range = pow2ceil(atoi(optarg));
             break;