ligo/src/lib_p2p/moving_average.ml
2018-06-30 17:41:32 +02:00

104 lines
3.6 KiB
OCaml

(*****************************************************************************)
(* *)
(* Open Source License *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
(* *)
(* Permission is hereby granted, free of charge, to any person obtaining a *)
(* copy of this software and associated documentation files (the "Software"),*)
(* to deal in the Software without restriction, including without limitation *)
(* the rights to use, copy, modify, merge, publish, distribute, sublicense, *)
(* and/or sell copies of the Software, and to permit persons to whom the *)
(* Software is furnished to do so, subject to the following conditions: *)
(* *)
(* The above copyright notice and this permission notice shall be included *)
(* in all copies or substantial portions of the Software. *)
(* *)
(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *)
(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *)
(* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER*)
(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *)
(* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *)
(* DEALINGS IN THE SOFTWARE. *)
(* *)
(*****************************************************************************)
open Lwt.Infix
module Inttbl = Hashtbl.Make(struct
type t = int
let equal (x: int) (y: int) = x = y
let hash = Hashtbl.hash
end)
type t = {
id: int;
alpha: int ;
mutable total: int64 ;
mutable current: int ;
mutable average: int ;
}
let counters = Inttbl.create 51
let updated = Lwt_condition.create ()
let update_hook = ref []
let on_update f = update_hook := f :: !update_hook
let worker_loop () =
let prev = ref @@ Mtime_clock.elapsed () in
let rec inner sleep =
sleep >>= fun () ->
let sleep = Lwt_unix.sleep 1. in
let now = Mtime_clock.elapsed () in
let elapsed = int_of_float (Mtime.Span.(to_ms now -. to_ms !prev)) in
prev := now;
Inttbl.iter
(fun _ c ->
c.average <-
(c.alpha * c.current) / elapsed + (1000 - c.alpha) * c.average / 1000;
c.current <- 0)
counters ;
List.iter (fun f -> f ()) !update_hook ;
Lwt_condition.broadcast updated () ;
inner sleep
in
inner (Lwt_unix.sleep 1.)
let worker =
lazy begin
Lwt.async begin fun () ->
Lwt_utils.worker "counter"
~run:worker_loop
~cancel:(fun _ -> Lwt.return_unit)
end
end
let create =
let cpt = ref 0 in
fun ~init ~alpha ->
Lazy.force worker ;
let id = !cpt in
incr cpt ;
assert (0. < alpha && alpha <= 1.) ;
let alpha = int_of_float (1000. *. alpha) in
let c = { id ; alpha ; total = 0L ; current = 0 ; average = init } in
Inttbl.add counters id c ;
c
let add c x =
c.total <- Int64.(add c.total (of_int x)) ;
c.current <- c.current + x
let destroy c =
Inttbl.remove counters c.id
type stat = {
total: int64 ;
average: int ;
}
let stat ({ total ; average } : t) : stat =
{ total ; average }