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


From: Leon Woestenberg
Subject: [lwip-users] Re: [lwip] lwIP on Gigabit Ethernet
Date: Thu, 09 Jan 2003 00:03:12 -0000

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.]
>

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