[dpdk-users] DPDK 2.2 MLX4: problem with number of TX/RX queues

[Vincent Li]

On Thu, Feb 11, 2016 at 1:36 PM, Harold Demure
<harold.demure87 at gmail.com> wrote:
> Hello Vincent,
>   Thank you for your reply. I followed the same reasoning as you did,
> looking at the source code earlier today.
>
> Can you send me a link that explains how to change RX for my NIC?
> I have been looking around for that, and also performed the steps in the
> DPDK official guide for MLX4, but apparently nothing changed (at least, the
> error was still there).
>

I am DPDK newbie too and no MLX4 nic to play with, I think you need to
find out how to enable RSS for MLX4

librte_pmd_mlx4/Makefile has some clue about RSS:

mlx4_autoconf.h: $(RTE_SDK)/scripts/auto-config-h.sh
        $Q $(RM) -f -- '$@'
        $Q sh -- '$<' '$@' \
                RSS_SUPPORT \
                infiniband/verbs.h \
                enum IBV_EXP_DEVICE_UD_RSS $(AUTOCONF_OUTPUT)

maybe you can find the mlx4_autoconf.h and see if you have RSS_SUPPORT in it?

librte_pmd_mlx4/mlx4.c has:

#ifdef RSS_SUPPORT
                if (ibv_exp_query_device(ctx, &exp_device_attr)) {
                        INFO("experimental ibv_exp_query_device");
                        goto port_error;
                }
                if ((exp_device_attr.exp_device_cap_flags &
                     IBV_EXP_DEVICE_QPG) &&
                    (exp_device_attr.exp_device_cap_flags &
                     IBV_EXP_DEVICE_UD_RSS) &&
                    (exp_device_attr.comp_mask &
                     IBV_EXP_DEVICE_ATTR_RSS_TBL_SZ) &&
                    (exp_device_attr.max_rss_tbl_sz > 0)) {
                        priv->hw_qpg = 1;
                        priv->hw_rss = 1;
//<======================================
                        priv->max_rss_tbl_sz = exp_device_attr.max_rss_tbl_sz;
                } else {
                        priv->hw_qpg = 0;
                        priv->hw_rss = 0;
                        priv->max_rss_tbl_sz = 0;
                }
                priv->hw_tss = !!(exp_device_attr.exp_device_cap_flags &
                                  IBV_EXP_DEVICE_UD_TSS);
                DEBUG("device flags: %s%s%s",
                      (priv->hw_qpg ? "IBV_DEVICE_QPG " : ""),
                      (priv->hw_tss ? "IBV_DEVICE_TSS " : ""),
                      (priv->hw_rss ? "IBV_DEVICE_RSS " : ""));
                if (priv->hw_rss)
                        DEBUG("maximum RSS indirection table size: %u",
                              exp_device_attr.max_rss_tbl_sz);
#endif /* RSS_SUPPORT */

make sure you  meet MLX4 library dependencies that has
ibv_exp_query_device to query mlx4 properly to make sure priv->hw_rss
= 1 ?

after you enabled RSS, then figure out how to enable multiple RX
queues or maybe it will be enabled automatically.

or you can ask MLX4 community