On Nov 26, 2011, at 4:28 AM, Soumyendra Saha wrote:

> Many thanks  for your earlier reply.
> Though the load is not shared evenly I got a setting combining both FlowDir 
> and RSS that does a decent job.
> I am dealing with packets at  national gateway. Hence there are many 
> encapsulating headers like pseudowire, PPP,VLAN, MPLS etc...so the hardware 
> obviously is at a loss to parse all that and get to IP or TCP headers. Hence 
> the fallback to queue 0 ( from both FlowDir and RSS ) which is getting a high 
> amount of traffic in comparison.
> Hopefully I can distribute packets to cores/queues in a round robin fashion 
> with a hack in ixgbe. I don't need to track flows ( that will be done in 
> userspace ), just packets are fine spread across CPUs.
> 
I don;t see how you can do that. What you can do instead is to distribute (if 
possible) packets across queues based on the port.

> Who is supposed to set the timestamp on packets ? I can see all packets with 
> time offset 0.
the DNA driver does set the timestamp if you pass a buffer, if not (you pass a 
pointer) we return 0 as timestamp. This is because computing it is costly and 
not everyone needs it (e.g. if you route/bridge packets you don't care).
> Is it ixgbe / pf_ring / userland . gettimeofday() is very costly from 
> userspace. This is slowing down pfcount processing in my case I think( but I 
> need to verify that )

It is costly everywhere.

> 
> Also I found PF_RING pfring_open_multichannel() to create too many threads 
> (72 )for any number of RSS settings on a 32-cpu machine running kernel 2.6.38 
> with MQ=1,1 RSS=8,8 FlowDir=1,1
> 

I hope you can provide us a patch as I don't have a computer with so many CPU 
cores :-)

Luca


> Regards,
> Soumyendra
> 
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