ligo/vendors/tezos-modded/src/lib_p2p/p2p_io_scheduler.mli
2019-05-27 11:18:48 +02:00

113 lines
4.9 KiB
OCaml

(*****************************************************************************)
(* *)
(* Open Source License *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
(* *)
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(** Generic IO scheduling between file descriptors.
In order to use IO scheduling, the [register] function must be
used to make a file descriptor managed by a [scheduler].. It will
return a value of type [connection] that must be used to perform IO
on the managed file descriptor using this module's dedicated IO
functions (read, write, etc.).
Each connection is allowed a read (resp. write) quota, which is
for now fairly distributed among connections.
To each connection is associated a read (resp. write) queue where
data is copied to (resp. read from), at a rate of
max_download_speed / num_connections (resp. max_upload_speed /
num_connections).
*)
type connection
(** Type of a connection. *)
type t
(** Type of an IO scheduler. *)
val create:
?max_upload_speed:int ->
?max_download_speed:int ->
?read_queue_size:int ->
?write_queue_size:int ->
read_buffer_size:int ->
unit -> t
(** [create ~max_upload_speed ~max_download_speed ~read_queue_size
~write_queue_size ()] is an IO scheduler with specified (global)
max upload (resp. download) speed, and specified read
(resp. write) queue sizes (in bytes) for connections. *)
val register: t -> P2p_fd.t -> connection
(** [register sched fd] is a [connection] managed by [sched]. *)
val write:
?canceler:Lwt_canceler.t ->
connection -> MBytes.t -> unit tzresult Lwt.t
(** [write conn msg] returns [Ok ()] when [msg] has been added to
[conn]'s write queue, or fail with an error. *)
val write_now: connection -> MBytes.t -> bool
(** [write_now conn msg] is [true] iff [msg] has been (immediately)
added to [conn]'s write queue, [false] if it has been dropped. *)
val read_now:
connection -> ?pos:int -> ?len:int -> MBytes.t -> int tzresult option
(** [read_now conn ~pos ~len buf] blits at most [len] bytes from
[conn]'s read queue and returns the number of bytes written in
[buf] starting at [pos]. *)
val read:
?canceler:Lwt_canceler.t ->
connection -> ?pos:int -> ?len:int -> MBytes.t -> int tzresult Lwt.t
(** Like [read_now], but waits till [conn] read queue has at least one
element instead of failing. *)
val read_full:
?canceler:Lwt_canceler.t ->
connection -> ?pos:int -> ?len:int -> MBytes.t -> unit tzresult Lwt.t
(** Like [read], but blits exactly [len] bytes in [buf]. *)
val stat: connection -> P2p_stat.t
(** [stat conn] is a snapshot of current bandwidth usage for
[conn]. *)
val global_stat: t -> P2p_stat.t
(** [global_stat sched] is a snapshot of [sched]'s bandwidth usage
(sum of [stat conn] for each [conn] in [sched]). *)
val iter_connection: t -> (connection -> unit) -> unit
(** [iter_connection sched f] applies [f] on each connection managed
by [sched]. *)
val close: ?timeout:float -> connection -> unit tzresult Lwt.t
(** [close conn] cancels [conn] and returns after any pending data has
been sent. *)
val shutdown: ?timeout:float -> t -> unit Lwt.t
(** [shutdown sched] returns after all connections managed by [sched]
have been closed and [sched]'s inner worker has successfully
canceled. *)
val id : connection -> int