Add benchmark for stream.

dune-project

@@ -1 +1,2 @@
 (lang dune 1.11)
+(allow_approximate_merlin)

tests/bench_stream.ml

@@ -0,0 +1,91 @@
+(* Copyright (C) 2019  Petter A. Urkedal <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version, with the OCaml static compilation exception.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ *)
+
+open Lwt.Infix
+
+let data = List.init 100_000 begin fun i ->
+  let x = float_of_int (i + 1) in
+  1.0 /. (x *. x)
+end
+
+module Stream_blocking = Caqti_stream.Make (struct
+  type 'a future = 'a
+  let return x = x
+  let (>>=) x f = f x
+  let (>|=) x f = f x
+end)
+
+module Stream_lwt = Caqti_stream.Make (struct
+  type 'a future = 'a Lwt.t
+  let return = Lwt.return
+  let (>>=) = Lwt.(>>=)
+  let (>|=) = Lwt.(>|=)
+end)
+
+let rec seq_of_list xs () =
+  (match xs with
+   | [] -> Seq.Nil
+   | x :: xs' -> Seq.Cons (x, seq_of_list xs'))
+
+let test_list () =
+  let _ : float = List.fold_left (+.) 0.0 data in
+  ()
+
+let test_seq =
+  let seq = seq_of_list data in
+  fun () ->
+    let _ : float = Seq.fold_left (+.) 0.0 seq in
+    ()
+
+let test_stream_blocking =
+  let stream = Stream_blocking.of_list data in
+  fun () ->
+    let (_ : float) =
+      Stream_blocking.fold ~f:(+.) stream 0.0 |> function
+       | Ok x -> x
+       | Error (`Congested err) -> Caqti_common.absurd err
+    in
+    ()
+
+let test_stream_lwt =
+  let stream = Stream_lwt.of_list data in
+  fun () -> Lwt_main.run begin
+    let%lwt (_ : float) =
+      Stream_lwt.fold ~f:(+.) stream 0.0 >|= function
+       | Ok x -> x
+       | Error (`Congested err) -> Caqti_common.absurd err
+    in
+    Lwt.return_unit
+  end
+
+(*
+let test_lwt_stream =
+  let stream = Lwt_stream.of_list data in (* OBS: Not re-iterable. *)
+  fun () -> Lwt_main.run begin
+    let%lwt (_ : float) = Lwt_stream.fold (+.) stream 0.0 in
+    Lwt.return_unit
+  end
+*)
+
+let () =
+  let res = Benchmark.throughputN 30 [
+    "List", test_list, ();
+    "Seq", test_seq, ();
+    "Stream_blocking", test_stream_blocking, ();
+    "Stream_lwt", test_stream_lwt, ();
+  ] in
+  print_newline ();
+  Benchmark.tabulate res

tests/dune

@@ -90,6 +90,14 @@
   (deps (alias drivers) uris.conf)
   (action (setenv OCAMLPATH . (run %{test}))))
 
+; Benchmarks; opam install benchmark and run manually
+
+(executable
+  (name bench_stream)
+  (modules Bench_stream)
+  (preprocess (pps lwt_ppx))
+  (libraries benchmark caqti lwt lwt.unix))
+
 ; Fake META Files - used for dynamic linking of drivers
 
 (alias (name drivers))