diff --git a/bench/trace_fx.ml b/bench/trace_fx.ml
index cf55da8..b2c0b8f 100644
--- a/bench/trace_fx.ml
+++ b/bench/trace_fx.ml
@@ -14,6 +14,7 @@ let work ~dom_idx ~n () : unit =
 
     (* Thread.delay 1e-6 *)
     if dom_idx = 0 && _i mod 4096 = 0 then (
+      Trace_core.message "gc stats";
       let stat = Gc.quick_stat () in
       Trace_core.counter_float "gc.minor" (8. *. stat.minor_words);
       Trace_core.counter_float "gc.major" (8. *. stat.major_words)
diff --git a/src/fuchsia/fcollector.ml b/src/fuchsia/fcollector.ml
index 223def1..0f5b486 100644
--- a/src/fuchsia/fcollector.ml
+++ b/src/fuchsia/fcollector.ml
@@ -36,13 +36,15 @@ end = struct
     mutable data: (string * user_data) list array;
   }
 
+  let init_size_ = 1
+
   let create () : t =
     {
       len = 0;
-      span = BA1.create BA.Int64 BA.C_layout 64;
-      start_time_ns = BA1.create BA.Int64 BA.C_layout 64;
-      name = Array.make 64 "";
-      data = Array.make 64 [];
+      span = BA1.create BA.Int64 BA.C_layout init_size_;
+      start_time_ns = BA1.create BA.Int64 BA.C_layout init_size_;
+      name = Array.make init_size_ "";
+      data = Array.make init_size_ [];
     }
 
   let[@inline] cap self = Array.length self.name