diff --git a/cmds/atrace/atrace.cpp b/cmds/atrace/atrace.cpp
index 70164ea..9060937 100644
--- a/cmds/atrace/atrace.cpp
+++ b/cmds/atrace/atrace.cpp
@@ -186,7 +186,10 @@
         { REQ,      "events/cpufreq_interactive/enable" },
     } },
     { "sync",       "Synchronization",  0, {
-        { REQ,      "events/sync/enable" },
+        // before linux kernel 4.9
+        { OPT,      "events/sync/enable" },
+        // starting in linux kernel 4.9
+        { OPT,      "events/fence/enable" },
     } },
     { "workq",      "Kernel Workqueues", 0, {
         { REQ,      "events/workqueue/enable" },