[Fwd: Re: [Click] generating artificial delay]

[Simon Schuetz]

Hi,
I think I have to revise my recent postings.
It seems, that the click router is not the absolute bottleneck,
neither by using 
FromDevice(eth0) -> Queue -> DelayUnqueue(0.05) -> ToHost(eth0)
nor
FromDevice(eth0) -> Queue -> DelayShaper(0.05) -> ToDevice(eth2)

Tested with several TCP streams at a time, and found out that the total
troughput of those streams is far higher than with one stream. So the
limiting factor is probably the TCP configuration.

Sorry about that
Simon



On Fri, 2004-03-19 at 19:26, Eddie Kohler wrote:
> Simon Schuetz wrote:
> > Hi,
> > I am using the following configuration
> > FromDevice(eth0) -> Queue -> DelayUnqueue(0.05) -> ToHost(eth0)
> > FromDevice(eth2) -> Queue -> DelayUnqueue(0.05) -> ToHost(eth2)
> > This implies a round trip delay of 100ms.
> > It works, but I experience severe performance problems.
> > I tried to used only
> > FromDevice(eth2) -> Queue -> DelayUnqueue(0.1) -> ToHost(eth2)
> > so that there is only one queue to handle (but same round trip delay),
> > and got the same results. The maximum TCP throughput I measured using
> > IPerf is about 2.3 MBit/s. If I unload the click router module, I have a
> > round-trip delay of less than 1ms, and a throughput of about 70MBit/s.
> 
> Hi Simon,
> 
> Why are you sending the packets ToHost?  Why not ToDevice?
> 
> Can you measure the performance of
> 
> FromDevice(eth0) -> ToHost(eth0)
> FromDevice(eth2) -> ToHost(eth2)
> 
> -- is it any better?  (I'd guess not.)
> 
> Click is not designed to get maximum performance when Linux does most of 
> the routing.
> 
> Eddie
>