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Old 09-21-2016, 04:53 AM   #1
hardikgohil1988
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Network Hang Isssue


Hello,

I am working on LInux 3.2.0 kernel.since we had requirement to make kernel real time I am using RT-Preempt Patch.

There is network Hang issue found.

To simulate issue I run iperf -c serverip from my board.

after that no response from iperf.

I close and try to ping hence cannot ping anymore.

need to reboot the board.


Can any body help to analyse the problem ?
 
Old 09-21-2016, 08:31 PM   #2
AwesomeMachine
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Have you used iperf successfully in the past? Perhaps the network connection is bad. Can you do an ifconfig to check if the interface is up and configured when things go bad?
 
Old 09-21-2016, 10:05 PM   #3
hardikgohil1988
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Hello,

The problem here happens only after applying rt patch to the kernel and recompile.

without RT patch the are no issues.

The Network hangs when there is TX/RX of packets (As iperf does)

ping works as normal for RT Patch kernel.

Once I Iperf there is no response.

I suspect there is some Driver Issue.

Last edited by hardikgohil1988; 09-21-2016 at 11:02 PM.
 
Old 09-22-2016, 09:45 PM   #4
hardikgohil1988
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I debugging by printing method and this is observation

for TX the cpsw_tx_handler is not getting

after Queue a buffer for transmission to a network device in dev_queue_xmit cpsw_tx_handler is not getting called.
 
Old 09-24-2016, 11:57 AM   #5
AwesomeMachine
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I think you're experiencing a receive livelock condition that appears as a network link failure. In RT systems gigabit network cards must use soft irqs to prevent the system from being overrun by irq kernel threads. This form of interrupt handling is not necessarily compatible to all nic drivers. I don't have a step-by-step solution. You'll need to investigate further.
 
Old 09-25-2016, 08:38 PM   #6
hardikgohil1988
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How can I debug the problem.can you help me ?
 
  


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