Add support for running microbenchmarks on supported bitgenerators

.github/workflows/build-and-test.yml

@@ -55,6 +55,12 @@ jobs:
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
+      - name: Run microbenchmarks
+        run: |
+          opam install testu01 core_bench core_unix --yes
+          opam exec -- dune build bin
+          opam exec -- dune exec -- bench
+
       - name: Build Docs
         run: opam exec -- dune build @doc
 

README.md

@@ -63,6 +63,10 @@ $ dune exec -- crush pcg64
 
  All tests were passed
 ```
+## Benchmarks
+A utility to compare the performance of each bitgenerator's `next_uint64` function is provided.
+To compile the benchmark executor run `dune build bin`, and then run it using `dune exec -- bench`.
+Once the benchmark run has completed, a summary table will be displayed in stdout.
 
 
 [1]: https://codecov.io/gh/zoj613/bitgenerators/graph/badge.svg?token=KOOG2Y1SH5

bin/bench.ml

@@ -0,0 +1,36 @@
+open Bitgen
+
+module type S = sig
+    type t 
+    val next_uint64 : t -> Stdint.uint64 * t
+    val initialize : SeedSequence.t -> t
+end
+
+
+let make_bits (module M : S) =
+    let ss = SeedSequence.initialize [Stdint.Uint128.of_int 123456789] in
+    let t = ref (M.initialize ss) in
+    let bits () = match M.next_uint64 !t with
+        | (u, t') -> t := t'; u
+    in
+    bits
+
+
+let pairs = [
+    "PCG64", (module PCG64: S);
+    "SFC64", (module SFC64: S);
+    "Xoshiro256", (module Xoshiro256: S);
+    "Philox64", (module Philox64: S);
+]
+
+
+let make_fn (name, m) =
+    Core_bench.Bench.Test.create ~name:(name ^ ".next_uint64") (make_bits m)
+
+
+let () =
+    Stdlib.Random.init 123456789;
+    [Core_bench.Bench.Test.create ~name:"Stdlib.Random.bits64" (fun () -> Stdlib.Random.int64 Int64.max_int)] @
+    List.map make_fn pairs
+    |> Core_bench.Bench.make_command
+    |> Command_unix.run

bin/dune

@@ -1,5 +1,12 @@
 (executable
  (public_name crush)
- (name crush)
+ (modules crush)
  (ocamlopt_flags (:standard -O3))
  (libraries bitgenerators testu01))
+
+
+(executable
+ (public_name bench)
+ (modules bench)
+ (ocamlopt_flags (:standard -O3))
+ (libraries bitgenerators core_bench core_unix.command_unix))