diff --git a/src/tef/dune b/src/tef/dune
index 4e12b80..acacd95 100644
--- a/src/tef/dune
+++ b/src/tef/dune
@@ -3,4 +3,7 @@
   (name trace_tef)
   (public_name trace-tef)
   (synopsis "Simple and lightweight tracing using TEF/Catapult format, in-process")
-  (libraries trace.core mtime mtime.clock.os atomic unix threads))
+  (libraries trace.core mtime mtime.clock.os atomic unix threads
+             (select relax_.ml from
+                     (base-domain -> relax_.real.ml)
+                     ( -> relax_.dummy.ml))))
diff --git a/src/tef/mpsc_queue.ml b/src/tef/mpsc_queue.ml
index 378fa71..c40b62d 100644
--- a/src/tef/mpsc_queue.ml
+++ b/src/tef/mpsc_queue.ml
@@ -18,7 +18,7 @@ module Backoff = struct
   let once (b : t) : t =
     let actual_b = b + Random.int 4 in
     for _i = 1 to actual_b do
-      Domain.cpu_relax ()
+      Relax_.cpu_relax ()
     done;
     min (b * 2) 256
 end
diff --git a/src/tef/relax_.dummy.ml b/src/tef/relax_.dummy.ml
new file mode 100644
index 0000000..3c5fd6f
--- /dev/null
+++ b/src/tef/relax_.dummy.ml
@@ -0,0 +1 @@
+let cpu_relax () = ()
diff --git a/src/tef/relax_.real.ml b/src/tef/relax_.real.ml
new file mode 100644
index 0000000..f3dab5c
--- /dev/null
+++ b/src/tef/relax_.real.ml
@@ -0,0 +1 @@
+let cpu_relax = Domain.cpu_relax