diff --git a/src/lib_benchmark/generator.ml b/src/lib_benchmark/generator.ml
index dfc5ad2b900499b9003dfb5024dc80e1e3f49983..77a4882715862339ffc0351d0f0dbf20120731f7 100644
--- a/src/lib_benchmark/generator.ml
+++ b/src/lib_benchmark/generator.ml
@@ -45,6 +45,8 @@ type 'workload benchmark =
       measure : unit -> float;
     }
       -> 'workload benchmark
+      (** Calculated provides its own [measure] function, unlike the other
+      benchmarks where [Measure] module times their closures *)
   | Plain : {
       workload : 'workload;
       closure : unit -> unit;
diff --git a/src/lib_benchmark/measure.ml b/src/lib_benchmark/measure.ml
index 2f9fd0ce7b6e470c2a8f84dfec68cd04e4f46ad9..e7fd1b909d22e5b8b42b096b2e8ad8bc5cb83dca 100644
--- a/src/lib_benchmark/measure.ml
+++ b/src/lib_benchmark/measure.ml
@@ -372,6 +372,15 @@ module Time = struct
     dt
     [@@inline always]
 
+  let measure_lwt f =
+    let open Lwt.Syntax in
+    let bef = get_time_ns () in
+    let+ res = f () in
+    let aft = get_time_ns () in
+    let dt = Int64.(to_float (sub aft bef)) in
+    (dt, res)
+    [@@inline always]
+
   let measure_and_return f =
     let bef = get_time_ns () in
     let x = f () in
@@ -457,8 +466,15 @@ let perform_benchmark (type c t) (options : options)
     List.fold_left
       (fun workload_data benchmark_fun ->
         progress () ;
-        set_gc_increment () ;
-        Gc.compact () ;
+        let bench = benchmark_fun () in
+        (match bench with
+        | Generator.Calculated _ ->
+            (* Calculated already gets its measures.
+               No need to perform GC. *)
+            ()
+        | _ ->
+            set_gc_increment () ;
+            Gc.compact ()) ;
         let measure_plain_benchmark workload closure =
           let measures =
             compute_empirical_timing_distribution
@@ -469,7 +485,7 @@ let perform_benchmark (type c t) (options : options)
           in
           {workload; measures} :: workload_data
         in
-        match benchmark_fun () with
+        match bench with
         | Generator.Calculated {workload; measure} ->
             let measures = Array.init options.nsamples (fun _ -> measure ()) in
             let measures = Maths.vector_of_array measures in
diff --git a/src/lib_benchmark/measure.mli b/src/lib_benchmark/measure.mli
index f59f11fe2ce3207e8e9e6ffbe84bfafc8764359d..c0aa0b7ccf4ca2bda87e1adf94f1849c77f86281 100644
--- a/src/lib_benchmark/measure.mli
+++ b/src/lib_benchmark/measure.mli
@@ -82,3 +82,13 @@ val make_timing_probe :
   (module Compare.COMPARABLE with type t = 't) -> 't Generator.probe
 
 val get_free_variable_set : packed_measurement -> Free_variable.Set.t
+
+module Time : sig
+  (** All return nano seconds *)
+
+  val measure : (unit -> unit) -> float
+
+  val measure_and_return : (unit -> 'a) -> float * 'a
+
+  val measure_lwt : (unit -> 'a Lwt.t) -> (float * 'a) Lwt.t
+end
diff --git a/src/lib_shell_benchmarks/io_helpers.ml b/src/lib_shell_benchmarks/io_helpers.ml
index dbbf1c9eeb075cb6b4a0472e3a51c7c9c93240c9..c8741c5295f36334b07e23263ddf95801b81a6ba 100644
--- a/src/lib_shell_benchmarks/io_helpers.ml
+++ b/src/lib_shell_benchmarks/io_helpers.ml
@@ -179,14 +179,17 @@ module Key_map = struct
         | None -> None
         | Some subtree -> find_opt tl subtree)
 
-  let rec to_seq path acc tree =
+  let rec to_seq :
+      String_map.key list ->
+      (String_map.key list * 'a) Seq.t ->
+      'a t ->
+      (String_map.key list * 'a) Seq.t =
+   fun path acc tree ->
     match tree with
     | Leaf v -> fun () -> Seq.Cons ((List.rev path, v), acc)
     | Node map ->
-        String_map.fold
-          (fun seg subtree acc -> to_seq (seg :: path) acc subtree)
-          map
-          acc
+        Seq.concat_map (fun (seg, subtree) -> to_seq (seg :: path) acc subtree)
+        @@ String_map.to_seq map
 
   let to_seq tree = to_seq [] Seq.empty tree
 
diff --git a/src/lib_shell_benchmarks/io_stats.ml b/src/lib_shell_benchmarks/io_stats.ml
index cdb694f51b252b017896d88becb453e0687b1870..91463e16b542821bdba431ece7251ffb1403a4e3 100644
--- a/src/lib_shell_benchmarks/io_stats.ml
+++ b/src/lib_shell_benchmarks/io_stats.ml
@@ -90,14 +90,14 @@ let load_tree context key =
   Context.fold
     context
     key
-    ~order:`Sorted
+    ~order:`Undefined
     ~init:Io_helpers.Key_map.empty
     ~f:(fun path t tree ->
       let+ o = Context.Tree.to_value t in
       match o with
       | Some bytes ->
           let len = Bytes.length bytes in
-          Io_helpers.Key_map.insert path len tree
+          Io_helpers.Key_map.insert (key @ path) len tree
       | None -> tree)
 
 let context_statistics base_dir context_hash =