diff --git a/src/time.c b/src/time.c
index 53ac853..d768742 100644
--- a/src/time.c
+++ b/src/time.c
@@ -477,6 +477,16 @@
     typval_T	rettv;
     typval_T	argv[2];
 
+#ifdef FEAT_JOB_CHANNEL
+    if (ch_log_active())
+    {
+	callback_T *cb = &timer->tr_callback;
+
+	ch_log(NULL, "invoking timer callback %s",
+	       cb->cb_partial != NULL ? cb->cb_partial->pt_name : cb->cb_name);
+    }
+#endif
+
     argv[0].v_type = VAR_NUMBER;
     argv[0].vval.v_number = (varnumber_T)timer->tr_id;
     argv[1].v_type = VAR_UNKNOWN;
@@ -484,6 +494,10 @@
     rettv.v_type = VAR_UNKNOWN;
     call_callback(&timer->tr_callback, -1, &rettv, 1, argv);
     clear_tv(&rettv);
+
+#ifdef FEAT_JOB_CHANNEL
+    ch_log(NULL, "timer callback finished");
+#endif
 }
 
 /*