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

[Slava Ovsiienko]

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 at monjalon.net>
> Sent: Friday, January 29, 2021 18:50
> To: Carsten Andrich <carsten.andrich at tu-ilmenau.de>
> Cc: users at dpdk.org; Slava Ovsiienko <viacheslavo at 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
> >
> >
> 
> 
> 
>