Add minimalistic Accumulator benchmark

Author: polytypic

bench/bench_accumulator.ml

@@ -0,0 +1,56 @@
+open Kcas_data
+open Bench
+
+let run_one ~n_domains ?(factor = 1) ?(n_ops = 60 * factor * Util.iter_factor)
+    () =
+  let t = Accumulator.make 0 in
+
+  let n_ops_todo = Atomic.make n_ops |> Multicore_magic.copy_as_padded in
+
+  let init _ = () in
+
+  let work _ () =
+    let rec work () =
+      let n = Util.alloc n_ops_todo in
+      if n <> 0 then
+        let rec loop n =
+          if 0 < n then begin
+            Accumulator.incr t;
+            Accumulator.decr t;
+            loop (n - 2)
+          end
+          else work ()
+        in
+        loop n
+    in
+    work ()
+  in
+
+  let after () = Atomic.set n_ops_todo n_ops in
+
+  let times = Times.record ~n_domains ~init ~work ~after () in
+
+  let name metric =
+    Printf.sprintf "%s/%d worker%s, 0%% reads" metric n_domains
+      (if n_domains = 1 then "" else "s")
+  in
+
+  List.concat
+    [
+      Stats.of_times times
+      |> Stats.scale (1_000_000_000.0 /. Float.of_int n_ops)
+      |> Stats.to_json
+           ~name:(name "time per operation")
+           ~description:"Average time to increment accumulator" ~units:"ns";
+      Times.invert times |> Stats.of_times
+      |> Stats.scale (Float.of_int (n_ops * n_domains) /. 1_000_000.0)
+      |> Stats.to_json
+           ~name:(name "operations over time")
+           ~description:
+             "Number of operations performed over time using all domains"
+           ~units:"M/s";
+    ]
+
+let run_suite ~factor =
+  [ 1; 2; 4 ]
+  |> List.concat_map @@ fun n_domains -> run_one ~n_domains ~factor ()

bench/main.ml

@@ -3,6 +3,7 @@ let benchmarks =
     ("Kcas Loc", Bench_loc.run_suite);
     ("Kcas Xt", Bench_xt.run_suite);
     ("Kcas parallel CMP", Bench_parallel_cmp.run_suite);
+    ("Kcas_data Accumulator", Bench_accumulator.run_suite);
     ("Kcas_data Hashtbl", Bench_hashtbl.run_suite);
     ("Kcas_data Mvar", Bench_mvar.run_suite);
     ("Kcas_data Queue", Bench_queue.run_suite);