From c77b579caaf1c3e37dfcab909d26a15ea8f8186c Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Wed, 7 Jun 2023 21:23:15 -0400
Subject: [PATCH] bench: add `-niter` param

---
 Makefile          |  9 +++++----
 benchs/fib_rec.ml | 30 +++++++++++++++++-------------
 2 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/Makefile b/Makefile
index 451d30d2..d4af9c89 100644
--- a/Makefile
+++ b/Makefile
@@ -19,13 +19,14 @@ watch:
 DUNE_OPTS_BENCH?=--profile=release
 
 N?=40
+NITER?=3
 bench-fib:
 	@echo running for N=$(N)
 	dune build $(DUNE_OPTS_BENCH) benchs/fib_rec.exe
 	hyperfine \
-		'./_build/default/benchs/fib_rec.exe -psize=1 -n $(N)' \
-		'./_build/default/benchs/fib_rec.exe -psize=8 -n $(N)' \
-		'./_build/default/benchs/fib_rec.exe -psize=20 -n $(N)' \
-		'./_build/default/benchs/fib_rec.exe -n $(N) -seq'
+		'./_build/default/benchs/fib_rec.exe -niter $(NITER) -psize=1 -n $(N)' \
+		'./_build/default/benchs/fib_rec.exe -niter $(NITER) -psize=8 -n $(N)' \
+		'./_build/default/benchs/fib_rec.exe -niter $(NITER) -psize=20 -n $(N)' \
+		'./_build/default/benchs/fib_rec.exe -niter $(NITER) -n $(N) -seq'
 
 .PHONY: test clean
diff --git a/benchs/fib_rec.ml b/benchs/fib_rec.ml
index f2904438..36d8c704 100644
--- a/benchs/fib_rec.ml
+++ b/benchs/fib_rec.ml
@@ -16,31 +16,35 @@ let rec fib ~on x : int Fut.t =
 
 let () = assert (List.init 10 fib_direct = [ 1; 1; 2; 3; 5; 8; 13; 21; 34; 55 ])
 
-let run ~psize ~n ~seq () : unit =
-  let res =
-    if seq then (
-      Printf.printf "compute fib %d sequentially\n%!" n;
-      fib_direct n
-    ) else (
-      Printf.printf "compute fib %d with pool size=%d\n%!" n psize;
-      let pool = Pool.create ~min:psize () in
-      fib ~on:pool n |> Fut.wait_block_exn
-    )
-  in
-  Printf.printf "fib %d = %d\n%!" n res
+let run ~psize ~n ~seq ~niter () : unit =
+  let pool = lazy (Pool.create ~min:psize ()) in
+  for _i = 1 to niter do
+    let res =
+      if seq then (
+        Printf.printf "compute fib %d sequentially\n%!" n;
+        fib_direct n
+      ) else (
+        Printf.printf "compute fib %d with pool size=%d\n%!" n psize;
+        fib ~on:(Lazy.force pool) n |> Fut.wait_block_exn
+      )
+    in
+    Printf.printf "fib %d = %d\n%!" n res
+  done
 
 let () =
   let n = ref 40 in
   let psize = ref 16 in
   let seq = ref false in
+  let niter = ref 3 in
   let opts =
     [
       "-psize", Arg.Set_int psize, " pool size";
       "-n", Arg.Set_int n, " fib <n>";
       "-seq", Arg.Set seq, " sequential";
+      "-niter", Arg.Set_int niter, " number of iterations";
     ]
     |> Arg.align
   in
 
   Arg.parse opts ignore "";
-  run ~psize:!psize ~n:!n ~seq:!seq ()
+  run ~psize:!psize ~n:!n ~seq:!seq ~niter:!niter ()