Pitiful benchmark performance

Sebastian Strollo <>
Sat Jun 9 01:24:47 CEST 2001


 writes:

> Sebastian Strollo writes:
>
>  > of counting the number of bytes received in the echo test (instead of
>  > just size(Packet)) creates quite an overhead...
> 
> Yes, that's exactly what I thought.
> 
> So I changed the program and ran tests comparing the original and
> changed ones and there's no big difference. 

Hm, you are quite right. I guess when it comes to 19 bytes the
difference is insignifcant. So I kept that change, made the constant a
binary (using <<"...">>), changed the sockets to active mode and reran
the tests. This gained me 10-20% which still leaves Erlang way behind
the other implementations. One thought I had was that the other tests
are forking and are not being charged for both processes CPU
time. *But* I ran the C, perl and the Erlang version of the test on
the same machine and just the difference in wall clock is really
big. I don't know what is going on? Any takers?

/Sebastian

Results from a linux machine:

  % /usr/bin/time ./a.out 100000
  server processed 1900000 bytes
  0.32user 6.68system 0:07.07elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (95major+27minor)pagefaults 0swaps

  % /usr/bin/time ./echo.perl 100000
  server processed 1900000 bytes
  4.90user 7.91system 0:12.84elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (270major+225minor)pagefaults 0swaps
  
  % /usr/bin/time erl -noshell -noinput -s echo main 100000
  server processed 1900000 bytes
  32.98user 11.39system 0:45.78elapsed 96%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (632major+1099minor)pagefaults 0swaps
  
  % /usr/bin/time erl -noshell -noinput -s echo3 main 100000
  server processed 1900000 bytes
  26.44user 10.39system 0:38.45elapsed 95%CPU (0avgtext+0avgdata 0maxresident)k
  0inputs+0outputs (633major+1106minor)pagefaults 0swaps


--- echo.erl	Sat Jun  9 00:12:09 2001
+++ echo3.erl	Sat Jun  9 01:14:18 2001
@@ -4,10 +4,10 @@
 
 %%% TBD - need to add check for valid response.
 
--module(echo).
+-module(echo3).
 -export([main/0, main/1, client/2, server/1]).
 
--define(DATA, "Hello there sailor\n").
+-define(DATA, <<"Hello there sailor\n">>).
 
 main() -> main(['1']).
 main([Arg]) ->
@@ -18,7 +18,7 @@
     init:stop().
 
 create_server_sock() ->
-    {ok, LSock} = gen_tcp:listen(0, [binary, {packet, 0}, {active, false}]),
+    {ok, LSock} = gen_tcp:listen(0, [binary]),
     LSock.
 
 socket_port(Sock) ->
@@ -26,17 +26,16 @@
     Port.
 
 client(N, ServerPort) ->
-    {ok, Sock} = gen_tcp:connect("localhost", ServerPort,
-				 [binary, {packet, 0}, {active, false}]),
+    {ok, Sock} = gen_tcp:connect("localhost", ServerPort, [binary]),
     client_loop(N, Sock),
     gen_tcp:close(Sock).
 
 client_loop(0, Sock) -> ok;
 client_loop(N, Sock) ->
     ok = gen_tcp:send(Sock, ?DATA),
-    case gen_tcp:recv(Sock, 0) of
-	{ok, Packet} -> client_loop(N-1, Sock);
-	{error, closed} -> ok
+    receive
+	{tcp, Sock, _} -> client_loop(N-1, Sock);
+	{tcp_closed, Sock} -> ok
     end.
 
 server(LSock) ->
@@ -45,11 +44,11 @@
     gen_tcp:close(LSock).
 
 server_loop(Sock, Bytes) ->
-    case gen_tcp:recv(Sock, 0) of
-	{ok, Packet} ->
+    receive
+	{tcp, Sock, Packet} ->
 	    ok = gen_tcp:send(Sock, Packet),
-	    server_loop(Sock, Bytes + length(binary_to_list(Packet)));
-	{error, closed} ->
+	    server_loop(Sock, Bytes + size(Packet));
+	{tcp_closed, Sock} ->
 	    io:format("server processed ~w bytes~n", [Bytes]),
 	    gen_tcp:close(Sock)
     end.



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