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From: Carsten Andrich <carsten.andrich@tu-ilmenau.de>
To: users@dpdk.org
Subject: [dpdk-users] MLX5: Using packet send scheduling / packet pacing
Date: Fri, 29 Jan 2021 17:30:04 +0100
Message-ID: <43ddc3a8-a48f-0930-a2da-9e2fcdde1b98@tu-ilmenau.de> (raw)

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:
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,

[2] https://patches.dpdk.org/patch/73742/
[3] https://doc.dpdk.org/guides/nics/mlx5.html#run-time-configuration

             reply	other threads:[~2021-01-29 16:30 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-29 16:30 Carsten Andrich [this message]
2021-01-29 16:50 ` Thomas Monjalon
2021-01-29 18:04   ` Slava Ovsiienko
2021-01-30 10:54     ` Carsten Andrich
2021-01-30 13:13       ` Thomas Monjalon

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