Merge pull request #5900 from kit-ty-kate/bench-opamsystem-read

Benchmark OpamSystem.read

bench.Dockerfile

@@ -13,3 +13,4 @@ RUN git clone https://github.com/ocaml/opam-repository --depth 1
 RUN git -C opam-repository fetch origin $OPAMREPOSHA
 RUN git -C opam-repository checkout $OPAMREPOSHA
 RUN opam init -n --disable-sandboxing ./opam-repository
+RUN find "$(pwd)/opam-repository" -name opam -type f > /home/opam/all-opam-files

master_changes.md

@@ -131,6 +131,9 @@ users)
 
 ## Test
 
+## Benchmarks
+  * Benchmark OpamSystem.read [#5900 @kit-ty-kate]
+
 ## Reftests
 ### Tests
   * Add init scripts tests [#5864 @rjbou]

tests/bench/bench.ml

@@ -33,6 +33,21 @@ let () =
     launch "opam switch set-invariant core -n --sw two";
     time_cmd ~exit:0 (fmt "%s install magic-trace -y --fake --sw two" bin)
   in
+  let time_OpamSystem_read_10 =
+    let time_OpamSystem_read () =
+      let ic = Stdlib.open_in_bin "/home/opam/all-opam-files" in
+      let before = Unix.gettimeofday () in
+      let rec loop () =
+        match Stdlib.input_line ic with
+        | file -> ignore (OpamSystem.read file); loop ()
+        | exception End_of_file -> Unix.gettimeofday () -. before
+      in
+      loop ()
+    in
+    let n = 10 in
+    let l = List.init n (fun _ -> time_OpamSystem_read ()) in
+    List.fold_left (+.) 0.0 l /. float_of_int n
+  in
   let json = fmt {|{
   "results": [
     {
@@ -52,6 +67,11 @@ let () =
           "name": "Fake install with invariant",
           "value": %f,
           "units": "secs"
+        },
+        {
+          "name": "OpamSystem.read amortised over 10 runs",
+          "value": %f,
+          "units": "secs"
         }
       ]
     },
@@ -70,6 +90,7 @@ let () =
       time_misspelled_cmd
       time_install_cmd
       time_install_cmd_w_invariant
+      time_OpamSystem_read_10
       bin_size
   in
   print_endline json

tests/bench/dune

@@ -1,3 +1,3 @@
 (executable
  (name bench)
- (libraries unix))
+ (libraries unix opam-core))