<div dir="ltr">Hello,<br><br>I have run into a regression following an update to stable
dpdk-24.11 with a number of my Mellanox cx4/5/6 nics. This regression
occurs with all nics in my lab which have DevX disabled: using mstconfig
utility, I can see the flag UCTX_EN is not set.<br><br>Mainly, the issue is that the ports cannot be started, with the following error logs in the journal:<br><br><div style="margin-left:40px"> Set nb_rxd=1 (asked=512) for port=0<br> Set nb_txd=1 (asked=512) for port=0<br> starting port 0<br> Initializing port 0 [7c:fe:90:65:e6:54]<br> port 0: ntfp1 (mlx5_pci)<br> nb_rxq=2 nb_txq=2<br> rxq0=c9 rxq1=c25<br> txq0=c9 txq1=c25<br> port 0: rx_scatter=0 tx_scatter=0 max_rx_frame=1526<br> mlx5_net: port 0 number of descriptors requested for Tx queue 0 must be higher than MLX5_TX_COMP_THRESH, using 33 instead of 1<br> mlx5_net: port 0 increased number of descriptors in Tx queue 0 to the next power of two (64)<br> mlx5_net: port 0 number of descriptors requested for Tx queue 1 must be higher than MLX5_TX_COMP_THRESH, using 33 instead of 1<br> mlx5_net: port 0 increased number of descriptors in Tx queue 1 to the next power of two (64)<br> mlx5_net: Port 0 Rx queue 0 CQ creation failure.<br> mlx5_net: port 0 Rx queue allocation failed: Cannot allocate memory<br> rte_eth_dev_start(port 0) failed, error=-12<br> Failed to start port 0, set link down<br> Failed to start port 0<br></div><br>Looking
more precisely into the problem, it appears that the number of Rx and
Tx descriptors configured for my queues is 1. This happens because
mlx5_dev_infos_get() return a limit of 1 for both Rx and Tx, which is
unexpected. I identified this patch to be responsible for the
regression:<br><br>4c3d7961d9002: net/mlx5: fix reported Rx/Tx descriptor limits<br><a href="https://git.dpdk.org/dpdk/commit/?id=4c3d7961d9002bb715a8ee76bcf464d633316d4c" target="_blank">https://git.dpdk.org/dpdk/commit/?id=4c3d7961d9002bb715a8ee76bcf464d633316d4c</a><br><br>After
doing some debugging, I noticed that hca_attr.log_max_wq_sz is never
configured. This should be done in mlx5_devx_cmd_query_hca_attr() which
is called in this bit of code:<br><br><a href="https://git.dpdk.org/dpdk/tree/drivers/common/mlx5/mlx5_common.c#n681" target="_blank">https://git.dpdk.org/dpdk/tree/drivers/common/mlx5/mlx5_common.c#n681</a><br><br><div style="margin-left:40px"> /*<br> * When CTX is created by Verbs, query HCA attribute is unsupported.<br> * When CTX is imported, we cannot know if it is created by DevX or<br> * Verbs. So, we use query HCA attribute function to check it.<br> */<br> if (cdev->config.devx || cdev->config.device_fd != MLX5_ARG_UNSET) {<br></div><div style="margin-left:40px"><div style="margin-left:40px"> /* Query HCA attributes. */<br> ret = mlx5_devx_cmd_query_hca_attr(cdev->ctx, &cdev->config.hca_attr);<br> if (ret) {<br></div></div><div style="margin-left:40px"><div style="margin-left:40px"><div style="margin-left:40px"> DRV_LOG(ERR, "Unable to read HCA caps in DevX mode.");<br> rte_errno = ENOTSUP;<br> goto error;<br></div></div></div><div style="margin-left:40px"><div style="margin-left:40px"> }<br> cdev->config.devx = 1;<br></div></div><div style="margin-left:40px"> }<br> DRV_LOG(DEBUG, "DevX is %ssupported.", cdev->config.devx ? "" : "NOT ");<br></div><br><div>I
deduced that following the above patch, the correct value for maximum
Rx and Tx descriptors will only be set if DevX is enabled (see the if
condition on cdev->config.devx). If it is disabled, then maximum Rx
and Tx descriptors will be 1, which will make the ports fail to start.
Perhaps we should keep the previous default value (65535) if config.devx
== 0 (DevX off)? This could be done like this, for example:<br><br>diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c<br>index 7708a0b80883..8ba3eb4a32de 100644<br>--- a/drivers/net/mlx5/mlx5_ethdev.c<br>+++ b/drivers/net/mlx5/mlx5_ethdev.c<br>@@ -359,10 +359,12 @@ mlx5_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *info)<br> info->flow_type_rss_offloads = ~MLX5_RSS_HF_MASK;<br> mlx5_set_default_params(dev, info);<br> mlx5_set_txlimit_params(dev, info);<br>- info->rx_desc_lim.nb_max =<br>- 1 << priv->sh->cdev->config.hca_attr.log_max_wq_sz;<br>- info->tx_desc_lim.nb_max =<br>- 1 << priv->sh->cdev->config.hca_attr.log_max_wq_sz;<br>+ if (priv->sh->cdev->config.devx) {<br>+ info->rx_desc_lim.nb_max =<br>+ 1 << priv->sh->cdev->config.hca_attr.log_max_wq_sz;<br>+ info->tx_desc_lim.nb_max =<br>+ 1 << priv->sh->cdev->config.hca_attr.log_max_wq_sz;<br>+ }<br> if (priv->sh->cdev->config.hca_attr.mem_rq_rmp &&<br> priv->obj_ops.rxq_obj_new == devx_obj_ops.rxq_obj_new)<br> info->dev_capa |= RTE_ETH_DEV_CAPA_RXQ_SHARE;<br><br>Thanks in advance for your help.<br><br>Regards,<br>Edwin Brossette.<div class="gmail-yj6qo"></div><div class="gmail-adL"><br><br></div></div></div>