TCP stack throughput

Matthias Lang <>
Mon Jul 4 23:34:11 CEST 2005

Mickael Remond writes:
 > Joel Reymont wrote:
 > > So this means 500 simultanous connection requests on Solaris and  about 
 > > 300 on Mac OSX (FreeBSD). My question, I suppose, is whether  this is 
 > > high enough.
 > > 
 > > Is there a limitation in Erlang or is this maxing out the platform  TCP 
 > > stack?
 > > 
 > > What do you folks recon?
 > Hello,
 > I am not sure I understand your test quite well. Basically you are 
 > connecting and deconnecting very quickly. Is that the case ?
 > If this is the case, what are you trying to benchmark ?
 > Most of the time mesuring the TCP/IP throughput implies trying to know 
 > how much data can be processed through a TCP socket, but usually a long 
 > running one.

I'm with Mickael.

Your results could be interpreted as showing one _or more_ of the

   a) That your test client is the bottleneck

   b) That your test server is the bottleneck

   c) That the OS/tcp stack isn't really designed for the sort of
      use you're testing.

My gut feeling says (c), mainly because different people are reporting
fairly different behaviour from one OS to another. I've written a
quick and dirty C server which does something similar enough to the
erlang server to work with your client. You could experiment with it
to try and eliminate hypothesis (b).

The program works for me on linux 2.6.x. 


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