[lwip-users] Re: [lwip] lwIP on Gigabit Ethernet

[Jani Monoses]

Also make sure you are generous with TCP related settings in lwipopts.h
pbuf size also makes a lot of difference (default is 128 that's small)
I only did superficial benchmarks here but increasing TCP MSS, window
and other settings resulted in visible improvements.
Jani.
> > Also, how often do you call the TCP fast timer routine?
> 
> I call the fast timer routine every 200ms.  I have been suspicious of this
> from the start.  I call the slow_tmr() function every 500ms.  It seems like
> the slow_tmr function is when lwIP goes through the active pcb list and
> empties the unsent queues.  Is that correct? or am I totally wrong..
> 
> 
>  Thanks,
>  Chris
> 
> 
> 
> 
> Leon Woestenberg wrote:
> 
> > Hello Chris,
> >
> > in such a case I would start some profile testing:
> > 1) start with the Ethernet device driver sitting in a while(1) loop
> > sending out Ethernet packets.
> >
> > This is the maximum throughput o/t "bare hardware + bare software".
> >
> > 2) Do the same for IP packets (checksum overhead etc.)
> > 3) Try the same for TCP packets (maybe you can mimick an extremely big
> > receive window
> > on the receiving side?)
> >
> > Also, how often do you call the TCP fast timer routine?
> >
> > I do not have "I told you so" remarks. The source code is there.
> >
> > Regards, Leon Woestenberg.
> >
> > ----- Original Message -----
> > From: "Chris Borrelli" <address@hidden>
> > To: <address@hidden>
> > Sent: Wednesday, June 26, 2002 11:54 PM
> > Subject: [lwip] lwIP on Gigabit Ethernet
> >
> > > Just putting some information out there..
> > >
> > > I have a simple lwIP (0.5.3) echo application running on a gigabit
> > > Ethernet network - no OS, no sockets API, just the raw lwIP API.  The
> > > performance is much less than I thought it would be (~4Mb/sec).  Does
> > > anyone have any comments/suggestions or "I told you so" about this?
> > >
> > > The system that its running on is PPC405 @ 200Mhz with an on chip
> > > Ethernet MAC (one of our own).  The bare metal performance of the system
> > > (no tcp stack) is about 40Mb/sec - the MAC host interface and driver I
> > > am working with is not at all optimized (16-bit interface @ 50Mhz, no
> > > DMA, no interrupts...).  But adding lwIP drops the performance by 10x
> > > (from 40 downto 4).  That doesn't seem right...
> > >
> > > I took a look at the TCP stream.  It looks like host PC fills the window
> > > (1024) of the lwIP device, and then the connection is reduced to sending
> > > very very small tcp segments back and forth.
> > >
> > > Has anyone else seen similar issues?  I get similar performance on a
> > > 100Mb/sec line (~4Kb/sec data rate).
> > >
> > > Does anyone have any lwIP performance numbers for their applications???
> > >
> > >  -Chris
> > >
> > > [This message was sent through the lwip discussion list.]
> > >
> >
> > [This message was sent through the lwip discussion list.]
> 
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