Re: [dpdk-dev] Mellanox Flow Steering

["Zhou, Danny" <danny.zhou@intel.com>]

Currently, the DPDK PMD and NIC kernel driver cannot drive a same NIC device simultaneously. When you
use ethtool to setup flow director filter, the rules are written to NIC via ethtool support in kernel driver. But when
DPDK PMD is loaded to drive same device, the rules previously written by ethtool/kernel_driver will be invalid, so 
you may have to use DPDK APIs to rewrite your rules to the NIC again.

The bifurcated driver is designed to provide a solution to support the kernel driver and DPDK coexist scenarios, but
it has security concern so netdev maintainer rejects it.

It should not be a Mellanox hardware problem, if you try it on Intel NIC the result is same.

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Raghav Sethi
> Sent: Sunday, April 12, 2015 1:10 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] Mellanox Flow Steering
> 
> Hi folks,
> 
> I'm trying to use the flow steering features of the Mellanox card to
> effectively use a multicore server for a benchmark.
> 
> The system has a single-port Mellanox ConnectX-3 EN, and I want to use 4 of
> the 32 cores present and 4 of the 16 RX queues supported by the hardware
> (i.e. one RX queue per core).
> 
> I assign RX queues to each of the cores, but obviously without flow
> steering (all the packets have the same IP and UDP headers, but different
> dest MACs in the ethernet headers) each of the packets hits one core. I've
> set up the client such that it sends packets with a different destination
> MAC for each RX queue (e.g. RX queue 1 should get 10:00:00:00:00:00, RX
> queue 2 should get 10:00:00:00:00:01 and so on).
> 
> I try to accomplish this by using ethtool to set flow steering rules (e.g.
> ethtool -U p7p1 flow-type ether dst 10:00:00:00:00:00 action 1 loc 1,
> ethtool -U p7p1 flow-type ether dst 10:00:00:00:00:01 action 2 loc 2..).
> 
> As soon as I set up these rules though, packets matching them just stop
> hitting my application. All other packets go through, and removing the
> rules also causes the packets to go through. I'm pretty sure my application
> is looking at all the queues, but I tried changing the rules to try a rule
> for every single destination RX queue (0-16), and that doesn't work either.
> 
> If it helps, my code is based on the l2fwd sample application, and is here:
> https://gist.github.com/raghavsethi/416fb77d74ccf81bd93e
> 
> Also, I added the following to my /etc/init.d: options mlx4_core
> log_num_mgm_entry_size=-1, and restarted the driver before any of these
> tests.
> 
> Any ideas what might be causing my packets to drop? In case this is a
> Mellanox issue, should I be talking to their customer support?
> 
> Best,
> Raghav Sethi