netmap bridge can tranmit big packet in line rate ?

[Barney Cordoba]

--- On Tue, 5/21/13, Luigi Rizzo <rizzo at iet.unipi.it> wrote:

> From: Luigi Rizzo <rizzo at iet.unipi.it>
> Subject: Re: netmap bridge can tranmit big packet in line rate ?
> To: "Hooman Fazaeli" <hoomanfazaeli at gmail.com>
> Cc: freebsd-net at freebsd.org
> Date: Tuesday, May 21, 2013, 10:39 AM
> On Tue, May 21, 2013 at 06:51:12PM
> +0430, Hooman Fazaeli wrote:
> > On 5/21/2013 5:10 PM, Barney Cordoba wrote:
> > >
> > > --- On Tue, 5/21/13, liujie <liujie at 263.net>
> wrote:
> > >
> > >> From: liujie <liujie at 263.net>
> > >> Subject: Re: netmap bridge can tranmit big
> packet in line rate ?
> > >> To: freebsd-net at freebsd.org
> > >> Date: Tuesday, May 21, 2013, 5:25 AM
> > >> Hi, Prof.Luigi RIZZO
> > >>    
> > >>  Firstly i should thank you for netmap. I
> tried to send a
> > >> e-mail to you
> > >> yestoday, but it was rejected.
> > >>
> > >>  I used two machines to test netmap
> bridge. all with i7-2600
> > >> cpu and intel
> > >> 82599 dual-interfaces card.
> > >>
> > >>  One worked as sender and receiver with
> pkt-gen, the other
> > >> worked as bridge
> > >> with bridge.c.
> > >>
> > >>  as you said,I feeled comfous too when i
> saw the big packet
> > >> performance
> > >> dropped, i tried to change the memory
> parameters of
> > >> netmap(netmap_mem1.c
> > >> netmap_mem2.c),but it seemed that  can
> not resove the
> > >> problem.
> > >>   60-byte packet send 14882289
> pps  recv 
> > >> 13994753 pps
> > >>   124-byte 
>    
> > >>    send   8445770 pps
> 
> > >> recv    7628942 pps
> > >>   252-byte 
>    
> > >>    send   4529819 pps
> 
> > >> recv     3757843 pps
> > >>   508-byte 
>    
> > >>    send    2350815 pps 
> > >> recv    1645647 pps
> > >>   1514-byte   
>    send 
> > >>   814288 pps 
>    recv  489133
> > >> pps
> > > These numbers indicate you're tx'ing 7.2Gb/s with
> 60 byte packets and
> > > 9.8Gb/s with 1514, so maybe you just need a new
> calculator?
> > >
> > > BC
> > > _______________________________________________
> > >
> > AsBarney pointed outalready, your numbers are
> reasonable. You have almost saturated
> > the link with 1514 byte packets.In the case of 64 byte
> packets, you do not achieve line
> > rate probably because of the congestion on the bus.Can
> you show us "top -SI" output on the
> > sender machine?
> 
> the OP is commenting that on the receive side he is seeing a
> much
> lower number than on the tx side (A:ix1 489Kpps vs A:ix0
> 814Kpps).
> 
>     [pkt-gen -f tx ix0]-->--[ix0 bridge ]
>     [   HOST A     
>   ]     [    HOST B ]
>     [pkt-gen -f rx ix1]--<--[ix1   
>     ]
> 
> What is unclear is where the loss occurs.
> 
>     cheers
>     luigi

The ixgbe driver has mac stats that will answer that. Just look at the
sysctl output.

BC