RSS mode performance in ixgbe (82599) driver

Hi, everyone

I'm testing the RSS mode throughput of Intel ixgbe 82599 driver. My server's specification is Xeon 3GHz (4cores) and PCIe speed is 2.5Gx8lanes, and DD2 memory is about 600~700MHz.

When I enable the RSS(receive side scaling) mode with 4 Rx queues, the Rx performance is below than when I use a single queue.

I don't know how the cores operate, whether the cores run in sequence or simultaneously at the same time.

I want to know the mechanism in general how the multi-cores run and the reason why the performance of ixgbe driver in rss mode is below non-rss mode.

Thanks in advance.

Best Regards,
J.Hwan Kim

CC netdev, as these kind of stuff is better hosted on netdev

You should make sure your 4 rx queues are serviced by different cpus, or else, one cpu could be the bottleneck.

cat /proc/interrupts