[dpdk-dev] buf->hash.rss always empty with i40e

Bruce Richardson bruce.richardson at intel.com
Mon Jan 30 11:46:30 CET 2017

On Sat, Jan 28, 2017 at 11:48:36AM +0100, tom.barbette at ulg.ac.be wrote:
> Hi all,
> No matter the number of queues or the ETH_RSS_X parameter the mbuf->hash.rss field is empty using XL710 NICs. The exact same configuration gives me good hash value values with ixgbe/82599 cards.
> Any idea? I checked it is the same problem on 2.2 and 16.11. FlowDirector is not used.

It's hard to diagnose the exact problem without the full settings you
have tried, but one thing to watch out for that has caught me in the
past is that turning on RSS for IP packets, does not give an RSS value
if there is also TCP or UDP in the packets too. It only applies to IP
packets without TCP or UDP.

Here are settings that work for me with i40e driver:

        static const struct rte_eth_conf port_conf_default = {
                .rxmode = {
                        .mq_mode = ETH_MQ_RX_RSS,
                        .max_rx_pkt_len = ETHER_MAX_LEN
                .rx_adv_conf = {
                        .rss_conf = {
                                .rss_hf = ETH_RSS_IP | ETH_RSS_TCP | ETH_RSS_UDP,


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