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 utilite2 wired networking problem 
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Joined: Fri Apr 24, 2015 10:03 am
Posts: 3
Post utilite2 wired networking problem
I have a new utilite2 which I have been testing as a file server using samba.
I noticed that when I get a directory listing with a large number of files (>500) a few of the file names are corrupt (usually less than 12).
The files are systematically named so the corruption is easy to spot.
My initial test setup was using a windows-7 machine networked with the utilite2.
I then tested with a windows-xp machine networked with the utilite2. Same corruption occurred.
In switching to the windows-xp machine a different network switch was used so eliminating that.
I then used a packet sniffer to record the network traffic as it arrives to the pc. The corruption is present in the network packet.
In SMB packets, a file name is sent as multiple 2 byte sequences of 0 followed by <char>. The <char> is being set to 0 when the name is corrupted.
I then checked the directory listing using smbclient on the utilite2 which uses the samba interface but does not send the data via the network interface.
The listing is fine. All the network traffic is via the wired lan (eth0) not wireless.
I can of course continue to investigate this, but it gets harder to debug the lower in the kernel inspection is needed.
There is a new release of Linaro so one possibility is to try that, but the instruction of how to upgrade are rather opaque!
Given no checksum errors were being reported and tcp checksum offload is the default I decided to switch this off.
The corruption problem has vanished!
I have tested with windows-xp and windows-7 and both are now fine.
Clearly not using tcp checksum offload means a cpu hit.
Anyone else reporting this problem?
Is this a hardware fault with the board I have?


Fri Apr 24, 2015 10:22 am
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Joined: Thu Jan 16, 2014 8:59 am
Posts: 31
Post Re: utilite2 wired networking problem
Hi,

smacqueen wrote:
The listing is fine. All the network traffic is via the wired lan (eth0) not wireless.

Is it an option for you to check the wireless so the problem can be narrowed down a bit?

smacqueen wrote:
There is a new release of Linaro so one possibility is to try that, but the instruction of how to upgrade are rather opaque!

Well, the most straight-forward way would be to install as if this was a new install. Although if you decide to test it, you might require some additional kernel pathces (I can provide you those) to make the Ethernet work.

smacqueen wrote:
Given no checksum errors were being reported and tcp checksum offload is the default I decided to switch this off.
The corruption problem has vanished!

That is really good to know! Although it does not point to an exact failing component.

smacqueen wrote:
I have tested with windows-xp and windows-7 and both are now fine.
Clearly not using tcp checksum offload means a cpu hit.

Have you performed any particular performance tests?

smacqueen wrote:
Anyone else reporting this problem?
Is this a hardware fault with the board I have?

AFAIR, this is a first report of such kind of problem.
It does not look like h/w fault, but I can't say for sure.

The investigation will require some time.
Also we are planning to switch to a newer kernel code base, but it is not ready yet, so it will require some time.

Regards,
Igor.


Tue Apr 28, 2015 12:30 pm
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Joined: Fri Apr 24, 2015 10:03 am
Posts: 3
Post Re: utilite2 wired networking problem
Thanks for your reply.
In checking more carefully I discovered switching off tcp checksum offload switched off all the advanced NIC features, it is an all or nothing interface. So in cannot be assumed the problem was the NIC checksumming. The performance looks OK for me with the OS handling the network stack, so I can continue testing. I don't have an easy way to do a wireless test but I will try an organise it.
Since the NIC does basic packet handling with no issues, I agree it seems unlikely it is a hardware issue. I fully understand the difficulties in tracking in down!


Tue Apr 28, 2015 3:27 pm
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