I'm curious if/how I can set the number of tx/rx queues (or otherwise force all pkts to be received in a single queue) in the ixgbe driver. I'm using 3.5.7+ kernel.
Now, one might ask why? I have a bridging/network-impairment module that basically grabs all packets from a network device, puts them in a single queue (can't have re-ordering), and then transmits them later on a different port. When testing at 10G speeds, the processor the impairment module runs on and the processor the NICs are bound to matters quite a bit. I'm using an E5 processor, 4 cores, 4 hyper threads. I disable irqbalance for the testing described here. If I bind eth2 IRQs to processor 0x10 and eth3 to 0x20, then I can get 9.8Gbps bi-directional throughput (ie, basically line speed) when the impairment module is bound to cpu 1, 2, or 3. I only get about 7Gbps on cpu 0, for whatever reason. But, there is a catch. In my initial testing, I used pktgen with fixed values (ie, same source/dest addresses for every packet). I got to wondering about rx-queues, so I changed pktgen to generate millions of different destination IPs. Under this load, the system works much harder, and can only handle about 9Gbps throughput. Since I had pinned all irqs (all tx/rx queues) to the same processor, I didn't expect that spreading the packets among various rx queues would actually make a difference, but it does, as far as I can tell. So, to investigate this further, I want to try configuring the NIC to only use one rx queue. It should be sufficient to just disable whatever logic the NIC uses to steer packets in one queue or another, but from what I can tell, ethtool cannot change this for the ixgbe driver. Thanks, Ben -- Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
