[Click] Interrupts are stuck with an unqueue element

[Lorenzo Bianconi]

2010/2/26 Eddie Kohler <kohler at cs.ucla.edu>:
> Hi Lorenzo,
>
> There was probably a bug in the version of Click you were using.  Many bugs in
> Unqueue "notification" (the feature that lets ToDevice go to sleep if there is
> nothing to send) have been fixed.  ALso there must have been a Queue in
> between Unqueue and ToDevice, but whatever.
>
> E
>
>
> lorenzo.bianconi at alice.it wrote:
>> Hi all,
>>
>> I am using click 1.6.0 as kernel module and I have encontered some issues using an ethernet device.
>> In particular I have to use an unqueue element in order to stop and restart the node transmission and I noticed that the interrupts (from /proc/interrupts)
>> on the eth device are stuck and consequently the device introduces a high latency.
>> This is my configuration
>>
>> ||||||||||||||||||||||||||        |||||||||||||||||          |||||||||||||||||||||                   ||||||||||||||||||||
>> ||FromDevice|| ---> ||Queue||  --->  ||Unqueue||  ---> ... ---> ||Todevice||
>> ||||||||||||||||||||||||||        |||||||||||||||||        |||||||||||||||||||||                     ||||||||||||||||||||
>>
>> Is it possibile that this problem is due to an unqueue scheduling issue?? If I stop the click thread, disable the interface (ifconfig eth0 down)
>> and afterwards I restart the interface and the click thread the interrupt number restarts to grow and everyting works fine.
>> Is it possible that this problem could be due to the kernel which disables the interrupts and switches to polling-mode in order to avoid the "livelock" problem??
>> I am using a kernel 2.6.19
>>
>> I know this is a walkaround but is there a way to restart interrupts on eth device avoiding to restart click thread?
>>
>> Thank you very much!!!
>>
>> Best regards
>>
>> Lorenzo
>>
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Hi Eddie,

This bug is probably due to an irqpoll issue (I was using it in order
to avoid panic
during bootstrap). I solved the issue calling the enable_irq() /
disable_irq_nosync()
in a FromDevice handler (I know this is just a workaround, not a fix :-( )

Cheers

Lorenzo