[erlang-questions] help about process,why very slow.

Sean Hinde <>
Sat Feb 16 15:48:47 CET 2008


The problem here is almost certainly your use of {active, true}. The  
inbound mailbox will rapidly fill with a very large number of messages  
(1 million in your case), and this can cause the emulator to slow down  
during garbage collection.

You need to introduce some flow control. The {active,once} socket  
option is normally used for this.

Sean

On 16 Feb 2008, at 12:18, 瞄瞄 wrote:

> help!
>
> On Feb 16, 2008 11:32 AM, 瞄瞄 <> wrote:
> server code url
> http://icej.80s.net.cn/emssserver.erl
>
> On Sat, Feb 16, 2008 at 11:26 AM, 瞄瞄 <> wrote:
>
> Hello everyone! I recent study erlang familiar with the code to make a
> message transmitted server, have a problem!
>
> I development of the information transmitted server function:
> Aclient Bclient are connected to Server, and joined a group C, Aclient
> send message to group C , message will be transmitted to B by group C.
> SOCKET use the binary (active true), (2) packet.
>
> News Server design:
> Have a process responsible for monitoring all client even when the
> client connect server, another process (group_manager process)
> maintenance division List of members of the client group, each group
> (group process) to have an process within the group responsible for  
> the
> client to transmit message.
>
>
> Performance testing problems encountered by:
> A test of million sent to the SERVER message used on the finished  
> eight
> seconds, and automatic logoff, and the content of the message are the
> same, so, the test Lan network.
> SERVER through tcpdump monitor and indeed also in the eight seconds  
> are
> all the message at the end, and not from the message into the A,  
> however
> SERVER transmitted to the messages with for a very long time, over 10
> minutes, finally, I end of the process.
>
> In server,use top,the cpu is 99% by beam.smp.
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 31586 root 17 0 70564 18m 1868 S 99.9 0.9 15:46.12 beam.smp
>
> Is it a problem I designed a very slow ? Or as a result of the process
> of communication? What measures can be taken tuning?
>
> Thank you help!
>
> the server code
> # -module(emssserver).
> # -export([init/0]).
> # -define(TCP_OPTIONS,[binary,{packet, 2}, {active, true}, {reuseaddr,
> true}]).
> # -define(PORT,7000).
> # -define(Debug,"YES").
> #
> # -ifdef(Debug).
> # -define(DEBUG(Fmt, Args), io:format(Fmt, Args)).
> # -else.
> # -define(DEBUG(Fmt, Args), no_debug).
> # -endif.
> # -record(group,{name,gpid}).
> # -record(client, {name,pid,socket}).
> #
> # init()->
> # {ok, Listen} = gen_tcp:listen(?PORT, ?TCP_OPTIONS),
> # register(accept_connection, spawn(fun() -> accept_connection(Listen)
> end)),
> # register(group_manage, spawn(fun() -> group_manage([]) end)).
> #
> # accept_connection(Listen) ->%% listen new client connection
> # {ok, Socket} = gen_tcp:accept(Listen),
> # Pid = spawn(fun() -> client_recv(Socket,"","") end),
> # gen_tcp:controlling_process(Socket,Pid),
> # accept_connection(Listen).
> #
> # client_recv(Socket,ClientName,GroupPid)->%%client process recv
> # receive
> # {tcp, Socket, Bin} ->
> # ?DEBUG("Server recv Data\r\n",""),
> # case binary_to_term(Bin) of
> # {join,JoinName,ClientNameTmp}->%%client join
> # ?DEBUG("client_recv Join:~s ~s\r\n",[JoinName,ClientNameTmp]),
> # G=#group{name=JoinName},
> # group_manage ! {join,G,self()},%%get group pid
> # receive
> # {grouppid,GPid}->%%recv group pid
> # ?DEBUG("Client_recv grouppid ~w ~s\r\n",[GPid,ClientNameTmp]),
> # GPid!{join,Socket,ClientNameTmp,self()} %% send "join" msg to group
> # end,
> # client_recv(Socket,ClientNameTmp,GPid);
> # {send,GroupName,Msg}->%%send msg to group
> # ?DEBUG("client_recv Send:~s ~s\r\n",[GroupName,Msg]),
> # GroupPid!{send,ClientName,Msg},
> # client_recv(Socket,ClientName,GroupPid)
> # end;
> # {tcp_closed, Socket} ->
> # ?DEBUG("client_recv close\r\n",[])
> # end.
> #
> # group_manage(Group)->%%manage group member
> # ?DEBUG("group_manage start\r\n",[]),
> # receive
> # {join,JoinGroup,ClientPid}->
> # ?DEBUG("group_manage Join:~s\r\n",[JoinGroup#group.name]),
> # case lists:keysearch(JoinGroup#group.name, #group.name, Group) of
> # false ->
> # Pid=spawn(fun() -> group([]) end),
> # ?DEBUG("group_manage group pid~w\r\n",[Pid]),
> # ClientPid!{grouppid,Pid},%%return client_recv group pid
> # JoinGroupp = #group{name=JoinGroup#group.name,gpid=Pid},
> # Gs = [JoinGroupp|Group],
> # ?DEBUG("group_manage group:~w\r\n",[Gs]),
> # group_manage(Gs);
> # {value,SingleGroup} ->
> # ?DEBUG("group_manage group is set ~s\r\n",[SingleGroup#group.name]),
> # ClientPid!{grouppid,SingleGroup#group.gpid},
> # group_manage(Group)
> # end
> #
> # end.
> #
> # group(Client)->%%send msg to all
> # ?DEBUG("group \r\n",[]),
> # receive
> # {join,Socket,ClientName,CPid} ->
> # ?DEBUG("group ClientName ~s\r\n",[ClientName]),
> # ?DEBUG("group Client set ~w\r\n",[Client]),
> # case lists:keysearch(ClientName,#client.name,Client) of
> # false->
> # ?DEBUG("group new client\r\n",[]),
> # ClientNew = #client{name=ClientName,pid=CPid,socket=Socket},
> # ClientTmp = [ClientNew|Client],
> # group(ClientTmp);
> # {value,SingleClient}->
> # ?DEBUG("group client is set ~s\r\n",[SingleClient#client.name]),
> # group(Client)
> # end;
> # {send,ClientName,Msg}->
> # ?DEBUG("group recv client send ~s\r\n",[Msg]),
> # lists:foreach(fun(T)->send(ClientName,T,Msg) end,Client),
> # group(Client)
> # end,
> # ok.
> #
> # send(FClientName,TClientName,Msg)->
> # if
> # FClientName /= TClientName#client.name ->
> # ?DEBUG("send f:~s t:~s
> ~s\r\n",[FClientName,TClientName#client.name,Msg]),
> # M = {FClientName,Msg},
> # gen_tcp:send(TClientName#client.socket,term_to_binary(M));
> # true->
> # ?DEBUG("send from eq to\r\n",[])
> # end.
>
> the client code is "gen_tcp:send",iterative
>
> the code install three linux server.
>
>
>
>
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