Provide a separate executable to bench pfortuna with miou

bench/dune

@@ -2,4 +2,9 @@
  (names speed)
  (modules speed)
  (libraries mirage-crypto mirage-crypto-rng mirage-crypto-rng.unix
-   mirage-crypto-pk mirage-crypto-ec mirage-crypto-rng-miou-unix))
+   mirage-crypto-pk mirage-crypto-ec))
+
+(executables
+ (names miou)
+ (modules miou)
+ (libraries mirage-crypto-rng-miou-unix))

bench/miou.ml

@@ -0,0 +1,91 @@
+open Mirage_crypto
+
+module Time = struct
+
+  let time ~n f a =
+    let t1 = Sys.time () in
+    for _ = 1 to n do ignore (f a) done ;
+    let t2 = Sys.time () in
+    (t2 -. t1)
+
+  let warmup () =
+    let x = ref 0 in
+    let rec go start =
+      if Sys.time () -. start < 1. then begin
+        for i = 0 to 10000 do x := !x + i done ;
+        go start
+      end in
+    go (Sys.time ())
+
+end
+
+let burn_period = 2.0
+
+let sizes = [16; 64; 256; 1024; 8192]
+(* let sizes = [16] *)
+
+let burn f n =
+  let buf = Mirage_crypto_rng.generate n in
+  let (t1, i1) =
+    let rec loop it =
+      let t = Time.time ~n:it f buf in
+      if t > 0.2 then (t, it) else loop (it * 10) in
+    loop 10 in
+  let iters = int_of_float (float i1 *. burn_period /. t1) in
+  let time  = Time.time ~n:iters f buf in
+  (iters, time, float (n * iters) /. time)
+
+let mb = 1024. *. 1024.
+
+let throughput title f =
+  Printf.printf "\n* [%s]\n%!" title ;
+  sizes |> List.iter @@ fun size ->
+    Gc.full_major () ;
+    let (iters, time, bw) = burn f size in
+    Printf.printf "    % 5d:  %04f MB/s  (%d iters in %.03f s)\n%!"
+      size (bw /. mb) iters time
+
+let bm name f = (name, fun () -> f name)
+
+let benchmarks = [
+  bm "pfortuna" (fun name ->
+    let open Mirage_crypto_rng_miou_unix.Pfortuna in
+    Miou_unix.run ~domains:2 @@ fun () ->
+    let rng = Mirage_crypto_rng_miou_unix.(initialize (module Pfortuna)) in
+    let g = create () in
+    reseed ~g "abcd" ;
+    throughput name (fun buf ->
+        let buf = Bytes.unsafe_of_string buf in
+        generate_into ~g buf ~off:0 (Bytes.length buf));
+    Mirage_crypto_rng_miou_unix.kill rng) ;
+]
+
+let help () =
+  Printf.printf "available benchmarks:\n  ";
+  List.iter (fun (n, _) -> Printf.printf "%s  " n) benchmarks ;
+  Printf.printf "\n%!"
+
+let runv fs =
+  Format.printf "accel: %a\n%!"
+    (fun ppf -> List.iter @@ fun x ->
+      Format.fprintf ppf "%s " @@
+        match x with `XOR -> "XOR" | `AES -> "AES" | `GHASH -> "GHASH")
+    accelerated;
+  Time.warmup () ;
+  List.iter (fun f -> f ()) fs
+
+
+let () =
+  let seed = "abcd" in
+  let g = Mirage_crypto_rng.(create ~seed (module Fortuna)) in
+  Mirage_crypto_rng.set_default_generator g;
+  match Array.to_list Sys.argv with
+  | _::(_::_ as args) -> begin
+      try
+        let fs =
+          args |> List.map @@ fun n ->
+            snd (benchmarks |> List.find @@ fun (n1, _) -> n = n1) in
+        runv fs
+      with Not_found -> help ()
+    end
+  | _ -> help ()

bench/speed.ml

@@ -404,18 +404,6 @@ let benchmarks = [
     throughput name (fun buf ->
         let buf = Bytes.unsafe_of_string buf in
         generate_into ~g buf ~off:0 (Bytes.length buf))) ;
-
-  bm "pfortuna" (fun name ->
-    let open Mirage_crypto_rng_miou_unix.Pfortuna in
-    Miou_unix.run ~domains:2 @@ fun () ->
-    let rng = Mirage_crypto_rng_miou_unix.(initialize (module Pfortuna)) in
-    let g = create () in
-    reseed ~g "abcd" ;
-    throughput name (fun buf ->
-        let buf = Bytes.unsafe_of_string buf in
-        generate_into ~g buf ~off:0 (Bytes.length buf));
-    Mirage_crypto_rng_miou_unix.kill rng) ;
-
 ]
 
 let help () =