Sendfile in erlang

Sean Hinde <>
Fri Nov 14 17:42:14 CET 2003


On Friday, November 14, 2003, at 03:36  pm, Luke Gorrie wrote:

> Miguel Barreiro <> writes:
>
>> ObPerfData: a cycle of file:read() and gen_tcp:send() moving 4KB 
>> chunks
>> over 1000Base-T between 1GHz Pentium3 machines sustains a throughput 
>> of
>> about 55Mbps. A cycle of file:sendfile() calls sustains over 410Mbps 
>> down
>> the pipe. Make sure you have a well supported network card before 
>> trying.
>
> Great stuff!
>
> Could you please post your benchmark programs too? I'm curious to try
> the unoptimised version in Oprofile (best program of the year) and see
> what kills the performance - user/kernel copies, context switches,
> erlang GC, select(), etc. If I remember correctly, Per Bergqvist was
> sending 10Mbps through Erlang on Celerons with only a fraction of the
> CPU with the kpoll'ified emulator.

That would be superb. I was at a loss in my testing to see what was 
making things slow. Klacke mentioned to me sometime that he was getting 
much greater throughput once upon a time so I just put this down to LAN 
congestion..

Please share any results you get

Thanks,
Sean




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