TCP stack throughput

Roger Larsson <>
Tue Jul 5 18:27:41 CEST 2005


On Monday 04 July 2005 23.34, Matthias Lang wrote:
> 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
> following:
>
>    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.
>
> Matthias

What about the factorial - C version does not do it.
Isn't it possible that it creates a bigger CPU load than expected?
(due to using bignums)

/RogerL



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