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

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

[Song Yoong Siang]

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.

Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
---
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 06266aad2f99..6f7b15d6c6ed 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -79,7 +79,7 @@ static int open_xsk(int ifindex, struct xsk *xsk, __u32 queue_id)
 		.fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS,
 		.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,
 		.frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE,
-		.flags = XSK_UMEM__DEFAULT_FLAGS,
+		.flags = XDP_UMEM_TX_METADATA_LEN,
 		.tx_metadata_len = sizeof(struct xsk_tx_metadata),
 	};
 	__u32 idx = 0;
@@ -551,6 +551,7 @@ static void hwtstamp_enable(const char *ifname)
 {
 	struct hwtstamp_config cfg = {
 		.rx_filter = HWTSTAMP_FILTER_ALL,
+		.tx_type = HWTSTAMP_TX_ON,
 	};
 
 	hwtstamp_ioctl(SIOCGHWTSTAMP, ifname, &saved_hwtstamp_cfg);
-- 
2.34.1

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

[Stanislav Fomichev]

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?

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?

With the above addressed:
Acked-by: Stanislav Fomichev <sdf@fomichev.me>

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

[Song, Yoong Siang]

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?

>With the above addressed:
>Acked-by: Stanislav Fomichev <sdf@fomichev.me>

Thanks & Regards
Siang

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

[Stanislav Fomichev]

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.