diff --git a/Makefile b/Makefile
index 2efe05b..3c06dfc 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,19 @@
 
 NAME = sequence
 DOC = sequence.docdir/index.html
-TARGETS = sequence.cma sequence.cmxa sequence.cmi sequence.a 
+TARGETS = sequence.cma sequence.cmxa sequence.cmi sequence.a
 LIB = $(addprefix _build/, $(TARGETS)) 
 INSTALL = $(LIB) sequence.mli
 
 all:
 	ocamlbuild $(TARGETS) $(DOC)
 
+bench: all
+	ocamlbuild \
+		-cflags -I,`ocamlfind query extlib` \
+		-lflags -I,`ocamlfind query extlib` \
+		-package extlib -package unix bench.native
+
 tests:
 	ocamlbuild tests.native
 
diff --git a/bench.ml b/bench.ml
new file mode 100644
index 0000000..3dbef4d
--- /dev/null
+++ b/bench.ml
@@ -0,0 +1,46 @@
+open ExtLib
+
+(* sum of the ints in the list *)
+let sum_list_seq l =
+  Sequence.fold (+) 0 (Sequence.of_list l)
+
+(* sum of the ints in the list *)
+let sum_list_enum l =
+  Enum.fold (+) 0 (List.enum l)
+
+(* force the list *)
+let force_list_seq l =
+  Sequence.persistent (Sequence.of_list l)
+
+let force_list_enum l =
+  let enum = List.enum l in
+  Enum.force enum;
+  enum
+
+let make_list n =
+  Sequence.to_list (Sequence.int_range ~start:0 ~stop:n)
+
+let measure_time f x =
+  let start = Unix.gettimeofday () in
+  let y = f x in
+  let stop = Unix.gettimeofday () in
+  y, stop -. start
+
+let _ =
+  let n = int_of_string Sys.argv.(1) in
+  Format.printf "compare sum on lists of size %d@." n;
+  let l = make_list n in
+  Format.printf "list created, length %d@." (List.length l);
+  let x1, time_seq = measure_time sum_list_seq l in
+  let x2, time_enum = measure_time sum_list_enum l in
+  assert (x1 = x2);
+  Format.printf "time for fold: seq: %.3f, enum: %.3f@." time_seq time_enum;
+  let x1, time_seq = measure_time force_list_seq l in
+  let x2, time_enum = measure_time force_list_enum l in
+  Format.printf "%d, %d@." (Sequence.length x1) (Enum.count x2);
+  assert (Sequence.length x1 = Enum.count x2);
+  Format.printf "time for force: seq: %.3f, enum: %.3f@." time_seq time_enum;
+  ()
+
+(* ocamlfind ocamlopt -I `ocamlfind query sequence` -I `ocamlfind query extlib`
+  sequence.cmxa extLib.cmxa unix.cmxa bench.ml -o bench *)