https://github.com/michaelnisi/ring-benchmark

The ring benchmark from “Programming Erlang”
https://github.com/michaelnisi/ring-benchmark

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The ring benchmark from “Programming Erlang”

• Host: GitHub
• URL: https://github.com/michaelnisi/ring-benchmark
• Owner: michaelnisi
• Created: 2013-07-06T19:44:37.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-12-06T15:09:34.000Z (about 11 years ago)
• Last Synced: 2024-10-13T18:45:40.134Z (2 months ago)
• Language: Erlang
• Homepage:
• Size: 111 KB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# ring-benchmark

In his book *Programming Erlang*, Joe Armstrong demands:

> Write a ring benchmark. Create N processes in a ring. Send a message round the ring M times so that a total of N * M messages get sent. Time how long this takes for different values of N and M.

So, here goes:

```Erlang

-module(ring).

-export([send/2]).

%% @doc Send M messages through a ring of N processes.

send(M, N) ->

  statistics(runtime),

  H = lists:foldl(

    fun(Id, Pid) -> spawn_link(fun() -> loop(Id, Pid, M) end) end,

    self(),

    lists:seq(N, 2, -1)),

  {_, Time} = statistics(runtime),

  io:format("~p processes spawned in ~p ms~n", [N, Time]),

  statistics(runtime),

  H ! M,

  loop(1, H, M).

loop(Id, Pid, M) ->

  receive

    1 ->

      {_, Time} = statistics(runtime),

      io:format("~p messages sent in ~p ms~n", [M, Time]),

      exit(self(), ok);

    Index ->

      Pid ! Index - 1,

      loop(Id, Pid, M)

  end.

```

To try this in shell:

```

$ erl

> c(ring).

{ok,ring}

> ring:send(100000,10000).

10000 processes spawned in 50 ms

100000 messages sent in 170 ms

** exception exit: ok

3>

```