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How fast can Erlang send messages?

September 10th, 2006 tonyg

My previous post examined Erlang’s speed of process setup and teardown. Here I’m looking at how quickly messages can be sent and received within a single Erlang node. Roughly speaking, I’m seeing 3.4 million deliveries per second one-way, and 1.4 million roundtrips per second (2.8 million deliveries per second) in a ping-pong setup in the same environment as previously - a 2.8GHz Pentium 4 with 1MB cache.

Here’s the code I’m using - time_diff and dotimes aren’t shown, because they’re the same as the code in the previous post:

-module(ipctest).
-export([oneway/0, consumer/0, pingpong/0]).

oneway() ->
    N = 10000000,
    Pid = spawn(ipctest, consumer, []),
    Start = erlang:now(),
    dotimes(N - 1, fun () -> Pid ! message end),
    Pid ! {done, self()},
    receive ok -> ok end,
    Stop = erlang:now(),
    N / time_diff(Start, Stop).

pingpong() ->
    N = 10000000,
    Pid = spawn(ipctest, consumer, []),
    Start = erlang:now(),
    Message = {ping, self()},
    dotimes(N, fun () ->
               Pid ! Message,
               receive pong -> ok end
           end),
    Stop = erlang:now(),
    N / time_diff(Start, Stop).

consumer() ->
    receive
    message -> consumer();
    {done, Pid} -> Pid ! ok;
    {ping, Pid} ->
        Pid ! pong,
        consumer()
    end.

%% code omitted - see previous post

Entry Filed under: Technology, Programming, Erlang