Re: [PATCH bpf-next 1/1] selftests/bpf: Enable Tx hwtstamp in xdp_hw_metadata

[Stanislav Fomichev <stfomichev@gmail.com>]

On 12/05, Song, Yoong Siang wrote:
> On Wednesday, December 4, 2024 11:49 PM, Stanislav Fomichev <stfomichev@gmail.com> wrote:
> >On 12/04, Song Yoong Siang wrote:
> >> Set tx_type to HWTSTAMP_TX_ON to enable hardware timestamping for all
> >> outgoing packets.
> >>
> >> Besides, set XDP_UMEM_TX_METADATA_LEN flag to reserve tx_metadata_len bytes
> >> of per-chunk metadata.
> >
> >XDP_UMEM_TX_METADATA_LEN is missing after d5e726d9143c ("xsk: Require
> >XDP_UMEM_TX_METADATA_LEN to actuate tx_metadata_len"), so that make
> >sense. Maybe add a fixes tag?
> >
> 
> Sure. I will add the fixes tag and submit with "PATCH bpf" prefix
> in next version.
> 
> >And I don't see mlx5 looking at HWTSTAMP_TX anywhere in the drivers,
> >so I'm assuming that's why I didn't need HWTSTAMP_TX_ON during my tests..
> >Which device are you testing against? I do see some hwts_tx_en
> >checks in the stfmmac at least... Can you add these details to the
> >commit message and respin?
> >
> 
> I am testing on stmmac and igc drivers.
> You are right, stmmac needs it for hwts_tx_en check.
> Besides, igc needs it to set IGC_RING_FLAG_TX_HWTSTAMP flag.
> 
> Without this patch, user will need to manually enable tx hwts using
> command: sudo hwstamp_ctl -i eth0 -t 1 -r 1
> after start xdp_hw_metadata.
> 
> Therefore, adding HWTSTAMP_TX_ON is not a bug fix solution.
> I will separate this as another new patch to "PATCH bpf-next"
> and provide detail in commit message.
> 
> Btw, is mlx5 driver always enable Tx HWTS?

I don't remember doing anything special to enable it. And looking at
the code I also don't see any conditionals on HWTSTAMP_TX_ON.