Re: RSS mode performance in ixgbe (82599) driver

From: Eric Dumazet
Date: Tue Aug 09 2011 - 08:43:36 EST

Le mardi 09 aoÃt 2011 Ã 21:03 +0900, J.Hwan Kim a Ãcrit :
> 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.

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

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