Fix compile error
diff --git a/src/core/lib/iomgr/timer_generic.c b/src/core/lib/iomgr/timer_generic.c
index e3e0e7f..c7ce76a 100644
--- a/src/core/lib/iomgr/timer_generic.c
+++ b/src/core/lib/iomgr/timer_generic.c
@@ -500,7 +500,7 @@
     }
     if (grpc_timer_check_trace) {
       gpr_log(GPR_DEBUG,
-              "TIMER CHECK SKIP: now_atm=%" PRId64 " min_timer=%" PRId64,
+              "TIMER CHECK SKIP: now_atm=%" PRIdPTR " min_timer=%" PRIdPTR,
               now_atm, min_timer);
     }
     return 0;