feat(profile): add basic counters

src/tef/Sidekick_tef.real.ml

@@ -59,6 +59,21 @@ module Make () : P.BACKEND = struct
       pid tid ts name;
     ()
 
+  let emit_count_event ~name ~ts (cs : _ list) : unit =
+    let pid = Unix.getpid () in
+    let tid = Thread.id (Thread.self ()) in
+    emit_sep_ ();
+    Printf.fprintf oc
+      {json|{"pid": %d,"cat":"","tid": %d,"ts": %.2f,"name":"%s","ph":"C","args":{|json}
+      pid tid ts name;
+    List.iteri
+      (fun i (n, value) ->
+        if i > 0 then Printf.fprintf oc ",";
+        Printf.fprintf oc {json|"%s":%d|json} n value)
+      cs;
+    Printf.fprintf oc {json|}}|json};
+    ()
+
   let teardown () = teardown_ oc
 end
 

src/util/Profile.ml

@@ -5,6 +5,7 @@ module type BACKEND = sig
     name:string -> start:float -> end_:float -> unit -> unit
 
   val emit_instant_event : name:string -> ts:float -> unit -> unit
+  val emit_count_event : name:string -> ts:float -> (string * int) list -> unit
   val teardown : unit -> unit
 end
 
@@ -36,6 +37,15 @@ let[@inline] instant name =
     let now = B.get_ts () in
     B.emit_instant_event ~name ~ts:now ()
 
+let[@inline] count name cs =
+  if cs <> [] then (
+    match !out_ with
+    | None -> ()
+    | Some (module B) ->
+      let now = B.get_ts () in
+      B.emit_count_event ~name ~ts:now cs
+  )
+
 (* slow path *)
 let[@inline never] exit_full_ (module B : BACKEND) name start =
   let now = B.get_ts () in

src/util/Profile.mli

@@ -14,6 +14,7 @@ val exit : probe -> unit
 val with_ : string -> (unit -> 'a) -> 'a
 val with1 : string -> ('a -> 'b) -> 'a -> 'b
 val with2 : string -> ('a -> 'b -> 'c) -> 'a -> 'b -> 'c
+val count : string -> (string * int) list -> unit
 
 module type BACKEND = sig
   val get_ts : unit -> float
@@ -22,6 +23,7 @@ module type BACKEND = sig
     name:string -> start:float -> end_:float -> unit -> unit
 
   val emit_instant_event : name:string -> ts:float -> unit -> unit
+  val emit_count_event : name:string -> ts:float -> (string * int) list -> unit
   val teardown : unit -> unit
 end