From: Brian Candler <B.Candler@...>
Date: 2003-04-06T05:26:35+09:00
Subject: Re: Clarification: read/write slow, and TCPSocket and sys{read,write}


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On Fri, Apr 04, 2003 at 11:00:01AM +0900, Ryan Pavlik wrote:
> I haven't benchmarked it yet, but using the setsockopt you mention
> below speeds things up, probably by about 2x.  It's still way slower
> than it could/should be.
> 
> > Using DRb (druby) you can typically get around 50 round-trips per second. I
> > guess you're getting rather less than that.
> 
> I'll run a test to see, now, but still, 50/s over localhost is really
> unacceptably slow... it should easily get a thousand or two a second,

That's 50 complete RPC exchanges doing some non-trivial work.

If you are just timing bytes over a socket, then how about the attached pair
of programs: the client sends a 4 byte string, and the server simply
uppercases it and sends it back. On my P266MMX laptop, this runs at almost
exactly 1000 operations per second.

I think you should break down what you are doing in this way until you find
the bottleneck. One possible problem is if you are doing a lot of

   s.write(x)
   s.write(y)
   s.write(z)

then you could try replacing it with

   s.write(x+y+z)

since that will generate one TCP segment instead of three.

Regards,

Brian.

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require 'socket'
s = TCPSocket.new("127.0.0.1","1234")
s.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
1000.times do
  s.write("abcd")
  s.read(4)
end

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require 'socket'
a = TCPServer.new("127.0.0.1","1234")
s = a.accept
s.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
while str = s.read(4)
  s.write(str.upcase!)
end


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