Hello,
we are experiencing lots of dropped UDP packets on our TS-7260 in 2.6.
Using 2.4, everything is working fine. In 2.6, iperf reports (depending
on bandwidth used) up to 50% dropped packets. Neither ifconfig nor
/proc/net/dev show any errors or lost packets, though.
We also wrote a simple RFC 862 echo server which works fine on 2.4.
Souece and binary of the server are available at [1], as well as the
source for our test client. Using 2.6, we can make the server lose a
request with even light network or CPU load - even typing in a telnet
session is enough most times, an "ls -l" or a "find /" via telnet or
serial console is sure to trigger packet loss. Sometimes (but not very
often) it happens even without any intervention.
It doesn't seem to be a general ARM 2.6 problem, as everything works
fine on an NSLU2 (ixp420) using 2.6.16 and 2.6.21. We are only seeing
the problem on the 7260. It would be helpful if somebody who owns a
different ep93xx board could run the same test so we can localize the
problem and find out if it is something specific to the TS boards (such
as a missing/wrong hardware intialization in 2.6) or a general ep93xx
problem with 2.6.
Also, it's probaly not the ep93xx ethernet driver, as it also happens
with the older Cirrus driver and when using a USB ethernet adapter
(pegasus driver).
We tried the following kernels:
* 2.6.17.14-derevo19 (Cirrus eth driver) [2]
* 2.6.21 from TS [3]
* 2.6.21.5 (Cirrus tree) [4]
* 2.6.23/24 vanilla
* 2.4.26 from TS - working
The configs and images can be found at [5], along with the working NSLU2
config. You can boot them on (at least) a TS-7260 with nfsroot. There is
also a suitable root fs for the 2.6 kernels, for 2.4 we used the one
from TS. [6]
Note that you have to boot 2.6.17 with mem=8M if you have the 64MB
version, as the discontigmem patch didn't apply to 2.6.17.
To all the 2.6 kernels (except the binary from TS, obviously) we applied
a few patches to make them work on the TS-7260. [7]
Has anybody experienced similar network problems with 2.6?
Thanks for any ideas,
Oliver
[1] http://murli.34sp.com/o/ep93xx-eth/echo/
[2] http://www.wantstofly.org/~buytenh/ep93xx/
[3]
ftp://ftp.embeddedarm.com/ts-arm-linux-cd/binaries/ts-kernels/zImage-72xx-2.6.21-ts
[4] http://arm.cirrus.com/files/linux/packages/linux-2.6.21.5.tar.bz2
[5] http://murli.34sp.com/o/ep93xx-eth/
[6] ftp://ftp.embeddedarm.com/images/tslinux/ts7260-32-default
[7] http://murli.34sp.com/o/ep93xx-eth/patches/
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