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xmpp.chapril.org-ejabberd/src/shaper.erl
Christophe Romain 6a10916dda Let shaper cope with low resolution system clock
We no longer rely on getting unique values from clock source, so we need
to handle cope with systems which does not have a microsecond resolution
on system clock (such as MS Windows)
2016-04-29 10:57:34 +02:00

150 lines
4.4 KiB
Erlang

%%%----------------------------------------------------------------------
%%% File : shaper.erl
%%% Author : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : Functions to control connections traffic
%%% Created : 9 Feb 2003 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2016 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License along
%%% with this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------
-module(shaper).
-behaviour(ejabberd_config).
-author('alexey@process-one.net').
-export([start/0, new/1, new1/1, update/2,
get_max_rate/1, transform_options/1, load_from_config/0,
opt_type/1]).
-include("ejabberd.hrl").
-include("logger.hrl").
-record(maxrate, {maxrate = 0 :: integer(),
lastrate = 0.0 :: float(),
lasttime = 0 :: integer()}).
-record(shaper, {name :: {atom(), global},
maxrate :: integer()}).
-type shaper() :: none | #maxrate{}.
-export_type([shaper/0]).
-spec start() -> ok.
start() ->
mnesia:create_table(shaper,
[{ram_copies, [node()]},
{local_content, true},
{attributes, record_info(fields, shaper)}]),
mnesia:add_table_copy(shaper, node(), ram_copies),
load_from_config(),
ok.
-spec load_from_config() -> ok | {error, any()}.
load_from_config() ->
Shapers = ejabberd_config:get_option(
shaper, fun(V) -> V end, []),
case mnesia:transaction(
fun() ->
lists:foreach(
fun({Name, MaxRate}) ->
mnesia:write(#shaper{name = {Name, global},
maxrate = MaxRate})
end, Shapers)
end) of
{atomic, ok} ->
ok;
Err ->
{error, Err}
end.
-spec get_max_rate(atom()) -> none | non_neg_integer().
get_max_rate(none) ->
none;
get_max_rate(Name) ->
case ets:lookup(shaper, {Name, global}) of
[#shaper{maxrate = R}] ->
R;
[] ->
none
end.
-spec new(atom()) -> shaper().
new(none) ->
none;
new(Name) ->
MaxRate = case ets:lookup(shaper, {Name, global}) of
[#shaper{maxrate = R}] ->
R;
[] ->
none
end,
new1(MaxRate).
-spec new1(none | integer()) -> shaper().
new1(none) -> none;
new1(MaxRate) ->
#maxrate{maxrate = MaxRate, lastrate = 0.0,
lasttime = p1_time_compat:system_time(micro_seconds)}.
-spec update(shaper(), integer()) -> {shaper(), integer()}.
update(none, _Size) -> {none, 0};
update(#maxrate{} = State, Size) ->
MinInterv = 1000 * Size /
(2 * State#maxrate.maxrate - State#maxrate.lastrate),
Interv = (p1_time_compat:system_time(micro_seconds) - State#maxrate.lasttime) /
1000,
?DEBUG("State: ~p, Size=~p~nM=~p, I=~p~n",
[State, Size, MinInterv, Interv]),
Pause = if MinInterv > Interv ->
1 + trunc(MinInterv - Interv);
true -> 0
end,
NextNow = p1_time_compat:system_time(micro_seconds) + Pause * 1000,
Div = case NextNow - State#maxrate.lasttime of
0 -> 1;
V -> V
end,
{State#maxrate{lastrate =
(State#maxrate.lastrate +
1000000 * Size / Div)
/ 2,
lasttime = NextNow},
Pause}.
transform_options(Opts) ->
lists:foldl(fun transform_options/2, [], Opts).
transform_options({OptName, Name, {maxrate, N}}, Opts) when OptName == shaper ->
[{shaper, [{Name, N}]}|Opts];
transform_options({OptName, Name, none}, Opts) when OptName == shaper ->
[{shaper, [{Name, none}]}|Opts];
transform_options(Opt, Opts) ->
[Opt|Opts].
opt_type(shaper) -> fun (V) -> V end;
opt_type(_) -> [shaper].