mlx5: imissed / out_of_buffer counter always 0

[Erez Ferber]

Hi Daniel,

is the container running in shared or non-shared mode ?
For shared mode, I assume the kernel sysfs counters which DPDK relies on
for imissed/out_of_buffer are not exposed.

Best regards,
Erez

On Fri, 2 Jun 2023 at 18:07, Slava Ovsiienko <viacheslavo at nvidia.com> wrote:

> Hi, Daniel
>
>
>
> I would recommend to take the following action:
>
> - update the firmware, 16.33.xxxx looks to be outdated a little bit.
> Please, try 16.35.1012 or later.
>   mlx5_glue->devx_obj_create might succeed with the newer FW.
>
> - try to specify dv_flow_en=0 devarg, it forces mlx5 PMD to use rdma_core
> library for queue management
>  and kernel driver will  be aware about Rx queues being created and attach
> them to the kernel counter set
>
>
>
> With best regards,
> Slava
>
>
>
> *From:* Daniel Östman <daniel.ostman at ericsson.com>
> *Sent:* Friday, June 2, 2023 3:59 PM
> *To:* users at dpdk.org
> *Cc:* Matan Azrad <matan at nvidia.com>; Slava Ovsiienko <
> viacheslavo at nvidia.com>; maxime.coquelin at redhat.com;
> david.marchand at redhat.com
> *Subject:* mlx5: imissed / out_of_buffer counter always 0
>
>
>
> Hi,
>
>
>
> I’m deploying a containerized DPDK application in an OpenShift Kubernetes
> environment using DPDK 21.11.3.
>
> The application uses a Mellanox ConnectX-5 100G NIC through VFs.
>
>
>
> The problem I have is that the ETH stats counter imissed (which seems to
> be mapped to “out_of_buffer” internally in mlx5 PMD driver) is 0 when I
> don’t expect it to be, i.e. when the application doesn’t read the packets
> fast enough.
>
>
>
> Using GDB I can see that it tries to access the counter through
> /sys/class/infiniband/mlx5_99/ports/1/hw_counters/out_of_buffer but the
> hw_counters directory is missing so it will just return a zero value. I
> don’t know why it is missing.
>
> When looking at mlx5_os_read_dev_stat() I can see that there is an
> alternative way of reading the counter, through
> mlx5_devx_cmd_queue_counter_query() but under the condition that
> priv->q_counters are set.
>
> It doesn’t get set in my case because mlx5_glue->devx_obj_create() fails
> (errno 22) in mlx5_devx_cmd_queue_counter_alloc().
>
>
>
> Have I missed something?
>
>
>
> NIC info:
>
> Mellanox Technologies MT27800 Family [ConnectX-5] - 100Gb 2-port QSFP28
> MCX516A-CCHT
> driver: mlx5_core
> version: 5.0-0
> firmware-version: 16.33.1048 (MT_0000000417)
>
>
>
> Please let me know if I need to provide more information.
>
>
>
> Best regards,
>
> Daniel
>
>
>
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