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This is my driver information.

ethtool -i ethXX
driver: ixgbe
version: 3.9.15-NAPI
firmware-version: 0x800000a5
bus-info: 0000:04:00.0
supports-statistics: yes
supports-test: yes
supports-eeprom-access: yes
supports-register-dump: yes

Now I have an average traffic of 1/1.5 Gbps (75k packets per second) hitting this interface and I can see one/or more of the ksoftirqd threads going to 100%.

I tried enabling the rx-usecs/rx-frames option, but no improvement. A bit of latency is not an issue for me. I just want the ksoftirqd usage to go down.

I see the limit of rx-usecs is 1022, which is the usecs after which the next interrupt should be fired (thats my understanding, please correct me if I am wrong). Though it doesn't solve my problem.

rx-frames on other hand are not supported on this driver. Neither is there any support for "adaptive-rx".

What should be the next step I should be looking at? Any help is greatly appreciated.

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What CPU do you have? And what version of irqbalance are you running? – David Schwartz Sep 4 '12 at 11:27
@ David Its a 24 core machine. sample output from /proc/cpuinfo. processor : 23 vendor_id : GenuineIntel cpu family : 6 model : 44 model name : Intel(R) Xeon(R) CPU L5638 @ 2.00GHz I don't use irqbalance. Instead I have RSS enabled which distributes packets on 24 rx-queues and these queues are mapped to different cpus. – pandagirija Sep 4 '12 at 11:51
What are you using to map the queues to CPUs? (Also, I think your hardware only supports 4 queues.) – David Schwartz Sep 4 '12 at 12:02
Each of these rx-queues (eth-TxRx-0/1/..) have one irq line assigned to them (62/63/64/...). I am editing the smp_affinity bit map in /proc/irq/<irq_no>/smp_affinity which maps one queue to one cpu. I can see 24 eth-TXRX queues. – pandagirija Sep 4 '12 at 12:06
Have you tried the newest drivers from Intel's site? I find them to solve a lot of problems, the drivers that come with distros tend to lag behind quite a bit, which causes issues with newer hardware. – Marcin Sep 4 '12 at 12:49

Turn on rx-flow-hash if not already turned on for tcp4/udp4/tcp6/udp6 e.g.

ethtool -N ethX rx-flow-hash udp4 sdfn 
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