diff --git a/bench/dune b/bench/dune
new file mode 100644
index 0000000..c6fec56
--- /dev/null
+++ b/bench/dune
@@ -0,0 +1,4 @@
+
+(executable
+  (name trace1)
+  (libraries trace.core trace-tef))
diff --git a/bench/trace1.ml b/bench/trace1.ml
new file mode 100644
index 0000000..f194a0d
--- /dev/null
+++ b/bench/trace1.ml
@@ -0,0 +1,36 @@
+module Trace = Trace_core
+
+let ( let@ ) = ( @@ )
+
+let work ~n () : unit =
+  for _i = 1 to n do
+    let@ _sp =
+      Trace.with_span ~__FILE__ ~__LINE__ "outer" ~data:(fun () ->
+          [ "i", `Int _i ])
+    in
+    for _k = 1 to 10 do
+      let@ _sp = Trace.with_span ~__FILE__ ~__LINE__ "inner" in
+      ()
+    done;
+    Thread.delay 1e-6
+  done
+
+let main ~n ~j () : unit =
+  let domains = Array.init j (fun _ -> Domain.spawn (fun () -> work ~n ())) in
+  Array.iter Domain.join domains
+
+let () =
+  let@ () = Trace_tef.with_setup () in
+
+  let n = ref 10_000 in
+  let j = ref 4 in
+
+  let args =
+    [
+      "-n", Arg.Set_int n, " number of iterations";
+      "-j", Arg.Set_int j, " set number of workers";
+    ]
+    |> Arg.align
+  in
+  Arg.parse args ignore "bench1";
+  main ~n:!n ~j:!j ()
diff --git a/bench1.sh b/bench1.sh
new file mode 100755
index 0000000..134b4a1
--- /dev/null
+++ b/bench1.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+DUNE_OPTS="--profile=release --display=quiet"
+exec dune exec $DUNE_OPTS bench/trace1.exe -- $@