Re: [dpdk-users] MLX5: Using packet send scheduling / packet pacing

[Carsten Andrich <carsten.andrich@tu-ilmenau.de>]

Hi Slava,

thank you for the prompt response. I think the requirements for Packet 
Pacing should be added to Table 34.2(?) of the MLX5 docs [1].

Best regards,
Carsten

[1] https://doc.dpdk.org/guides/nics/mlx5.html#mlx5-offloads-support

On 29.01.21 19:04, Slava Ovsiienko wrote:
> Hi, Carsten
>
> To use packet pacing capability:
> - ConnectX-6DX or above is required
> - the NV settings should be configured (set timestamp to real-time UTC)
>
> With best regards,
> Slava
>
>> -----Original Message-----
>> From: Thomas Monjalon <thomas@monjalon.net>
>> Sent: Friday, January 29, 2021 18:50
>> To: Carsten Andrich <carsten.andrich@tu-ilmenau.de>
>> Cc: users@dpdk.org; Slava Ovsiienko <viacheslavo@nvidia.com>
>> Subject: Re: [dpdk-users] MLX5: Using packet send scheduling / packet pacing
>>
>> 29/01/2021 17:30, Carsten Andrich:
>>> Hello everyone,
>>>
>>> I'm trying to use packet send scheduling [1] with DPDK 20.11 and the
>>> MLX5 PMD (NIC: ConnectX-5 MCX516A-CDAT). This patch contains some
>>> additional information on this feature also know as packet pacing [2].
>>>
>>> According to MLX5's docs, packet pacing requires the "tx_pp" parameter
>>> [3, CTRL+F: "tx_pp"]. However, when firing up testpmd with that
>>> parameter, it fails as follows:
>>>
>>>> # dpdk-testpmd -a 81:00.0,tx_pp=500 -- -i ...
>>>> EAL: Probe PCI driver: mlx5_pci (15b3:1019) device: 0000:81:00.0
>>>> (socket 0)
>>>> mlx5_pci: WQE rate mode is required for packet pacing
>>>> mlx5_pci: probe of PCI device 0000:81:00.0 aborted after
>>>> encountering an error: No such device
>>>> common_mlx5: Failed to load driver = mlx5_pci.
>>>>
>>>> EAL: Requested device 0000:81:00.0 cannot be used
>>> The error message originates here [4] and is caused by what to me
>>> appears to be a value read from the NIC [5]. Unfortunately, that
>>> leaves me clueless on how to activate the required "WQE rate mode".
>>> According to the output of ibv_devinfo, my NIC does support packet pacing:
>>>
>>>> # ibv_devinfo -v 81:00.0
>>>> ...
>>>> 	packet_pacing_caps:
>>>> 		qp_rate_limit_min:	1kbps
>>>> 		qp_rate_limit_max:	100000000kbps
>>>> 		supported_qp:
>>>> 					SUPPORT_RAW_PACKET
>>> I'd be grateful for any information on how to get packet pacing up and
>>> running. Am I just missing another required option (which is not given
>>> in the docs) or does my NIC lack packet pacing support?
>>>
>>> Thank you very much in advance.
>>>
>>> Best regards,
>>> Carsten
>>>
>>> [1]
>>>
>> https://doc.dpdk.org/api/rte__ethdev_8h.html#a990d8351447a710628cbb24
>> a
>>> 28d3252d [2] https://patches.dpdk.org/patch/73742/
>>> [3] https://doc.dpdk.org/guides/nics/mlx5.html#run-time-configuration
>>> [4]
>>> http://code.dpdk.org/dpdk/v20.11/source/drivers/net/mlx5/linux/mlx5_os
>>> .c#L1278
>>> [5]
>>>
>> http://code.dpdk.org/dpdk/v20.11/source/drivers/common/mlx5/mlx5_devx
>> _
>>> cmds.c#L748
>>>
>>>
>>
>>
>>