Device polling heavy traffic

Mihai Tanasescu mihai at
Mon Dec 26 13:24:28 PST 2005


I'm running the following  setup:

Freebsd Dual Xeon 3Ghz machine (SMP enabled)

3 x 100 Mbits/s links (used at 80% capacity)  - 3 x Intel  100 fxp

1 x 1000 Gbit link to a cisco router (transfers downstream the other  3 
links) - 1 x Intel em

I'm getting something arround 100k pkt/sec input and 100k pkt/sec output 
as "systat -ip 1" shows.

Kernel polling is enabled.
I have tried options HZ=1000, options  HZ=2500 to see if anything changes.

The problem:
If I ping this machine or anything that is routed through it I get 
response times of 10-15-30 ms and once in 30 seconds a packet is lost.

If I disable kernel.polling.enable then I get response times of 1-2-3 ms 
but I also get a lot of interrupts and a kernel panic after about 20 min.

I was wondering what else I could try to change or what settings would 
be the best choice in order to have polling enabled and to avoid packet 
loss for small packets that also require low delays.

I'm sorry if this wasn't the appropriate list to post  to,

Thanks in advance,


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