Help: FreeBSD 6.3 - em driver & taskqueue & priority

Joe Kuan joe.kuan at
Tue Jul 8 12:26:38 UTC 2008

On 8 Jul 2008, at 12:35, Ivan Voras wrote:

> Joe Kuan wrote:
>> Hi all,
>>   I have implemented an network application in kernel space and it is
>> working fine. The application involves 3 network interfaces that  
>> FreeBSD
>> 6.3 can forward mbuf between em0 and em1 in a rate 1.3 - 1.4 millions
>> packets per second. Em2 is used for controlling the network  
>> application.
>>   The problem is that when em0 and em1 are transmitting in 1.3 - 1.4
>> millions packets per second, the em2 interface becomes irresponsive.
>> However, my goal is to make the kernelised network application  
>> response
>> as soon as a control packet arrives in em2, ie jumps the queue  
>> ahead of
>> all the packets in em0 and em1.
>>   I think the problem lies on the priority set on the task structure
>> are all the same for all the em devices. Am I heading in the right
>> direction?
> A wild theory: are the NICs separate / individual and on separate  
> buses?
> If they are not (e.g. two of them are on the same card or bus) it  
> might
> be a hardware issue.
em0 and em1 are on the same card. Em2 is on the separate card.


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