Chelsio T520-SO-CR low performance (netmap tested) for RX

[Navdeep Parhar]

On Sat, Jan 23, 2016 at 03:48:39PM -0200, Marcus Cenzatti wrote:
...
> 
> woops, my bad, yes probably we had some drop, with -S and -D now I get 1.2Mpps.

Run "netstat -hdw1 -i cxl<n>" on the receiver during your test.  Do you
see errs and/or idrops incrementing?  The input "packets" counter should
match what the transmitter is claiming to transmit at.

Also check the output of this:
# sysctl -n dev.t5nex.0.misc.tp_err_stats
It is ok if you see tnlCongDrops, but any of the Errs counter going up
is not good -- it means the incoming frames had errors.

Do you know if the transmitter will pad up so as not to put runts on the
wire?  If not then you might want to bump up the size of the frame
explicitly (there's some pkt-gen knob for this).

Regards,
Navdeep

> 
> curiously, I have always used -s/-d with IP addresses on ix-ix testing this is
> why I never noticed the case, since ix always received 14Mpps, but you
> probably explained it since ix has one single deviceport per wire, hence the
> different behavior
> 
> performance stills very low when compared to TX and to what is expected
> 
> thank you for noticing the case
> 
> 
>