Issues with a Large Fat pipe Network simulation

[Luigi Rizzo]

On Mon, Jun 20, 2005 at 10:11:27PM +0200, Pieter de Boer wrote:
> Hello there,
...
> When testing without any extra delay on 'network' and send/recvspaces of
> 65535 bytes, we can sustain around 800mbit/s. The interrupts on
> 'network' may be the limiting factor here. However, when we set the
> send/recv space to 65535*2, we can only sustain around 200-300mbit/s. It

have you checked that these two
	kern.ipc.maxsockbuf: 262144
	kern.ipc.sockbuf_waste_factor: 8

aren't responsible for the trouble ?
I won't enter into details because i am not sure but try upping
maxsockbuf might help. Or not. in any case it would be nice to try
and let us know

	cheers
	luigi

> seems the speed isn't as 'stable' either (peaks of more than 300mbit/s,
> sometimes up to 500mbit/s). We also used read/write sizes of 128KB using
> the -l option on iperf, but this didn't seem to have any  noticeable
> effect.
> 
> When adding extra latency on 'network' and adjusting the
> send/recv-spaces to correct for the greater bandwidth*delay product, we
> weren't able to sustain rates much higher than 200mbit/s either.
> 
> 
> Can anyone shed some light on what we're seeing here?
> 
> -- 
> With regards,
> Pieter de Boer
> 
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