[PATCH v3 03/9] common/mlx5: extend SQ modify to support rate limit update

[Slava Ovsiienko]

Hi,

> -----Original Message-----
> From: Vincent Jardin <vjardin at free.fr>
> Sent: Friday, March 13, 2026 12:01 AM
> To: dev at dpdk.org
> Cc: Raslan Darawsheh <rasland at nvidia.com>; NBU-Contact-Thomas Monjalon
> (EXTERNAL) <thomas at monjalon.net>; andrew.rybchenko at oktetlabs.ru;
> Dariusz Sosnowski <dsosnowski at nvidia.com>; Slava Ovsiienko
> <viacheslavo at nvidia.com>; Bing Zhao <bingz at nvidia.com>; Ori Kam
> <orika at nvidia.com>; Suanming Mou <suanmingm at nvidia.com>; Matan Azrad
> <matan at nvidia.com>; stephen at networkplumber.org; Vincent Jardin
> <vjardin at free.fr>
> Subject: [PATCH v3 03/9] common/mlx5: extend SQ modify to support rate limit
> update
> 
> Add rl_update and packet_pacing_rate_limit_index fields to
> mlx5_devx_modify_sq_attr. When rl_update is set, the modify SQ command
> sets modify_bitmask bit 0 and writes the PP index into the SQ context, allowing
> dynamic rate changes on a live RDY SQ without teardown.
> 
> modify_sq_in.modify_bitmask[0x40] bit 0 controls the
> packet_pacing_rate_limit_index.
> 
> Supported hardware:
> - ConnectX-6 Dx: per-SQ rate via packet_pacing_rate_limit_index
> - ConnectX-7/8: same SQ context field, also supports wait-on-time
> - BlueField-2/3: same modify_sq command support
> 
> Not supported:
> - ConnectX-5: supports packet_pacing but only at SQ creation time,
>   dynamic modify_bitmask update may not be supported on all FW
> - ConnectX-4 Lx and earlier: no packet_pacing support
> 
> Signed-off-by: Vincent Jardin <vjardin at free.fr>
> ---
>  drivers/common/mlx5/mlx5_devx_cmds.c | 5 +++++
> drivers/common/mlx5/mlx5_devx_cmds.h | 3 +++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/drivers/common/mlx5/mlx5_devx_cmds.c
> b/drivers/common/mlx5/mlx5_devx_cmds.c
> index 8f53303fa7..17378e1753 100644
> --- a/drivers/common/mlx5/mlx5_devx_cmds.c
> +++ b/drivers/common/mlx5/mlx5_devx_cmds.c
> @@ -2129,6 +2129,11 @@ mlx5_devx_cmd_modify_sq(struct mlx5_devx_obj
> *sq,
>  	MLX5_SET(sqc, sq_ctx, state, sq_attr->state);
>  	MLX5_SET(sqc, sq_ctx, hairpin_peer_rq, sq_attr->hairpin_peer_rq);
>  	MLX5_SET(sqc, sq_ctx, hairpin_peer_vhca, sq_attr-
> >hairpin_peer_vhca);
> +	if (sq_attr->rl_update) {
> +		MLX5_SET64(modify_sq_in, in, modify_bitmask, 1);

1. Please define enum for the bit: MLX5_MODIFY_SQ_IN_MODIFY_BITMASK_PACKET_PACING_RATE_LIMIT_INDEX
(please see MLX5_MODIFY_RQ_IN_MODIFY_xxx enum). Also no objections to define enums for other
MLX5_MODIFY_SQ_IN_MODIFY_BITMASK _xxx.

2. Please modify only the involved bits in the bitmask:

uint64_t bitmask;

bitmask = MLX5_GET64(modify_sq_in, in, modify_bitmask);
bitmask |= MLX5_MODIFY_SQ_IN_MODIFY_BITMASK_PACKET_PACING_RATE_LIMIT_INDEX;
MLX5_SET64(modify_sq_in, in, modify_bitmask, bitmask);

This would improve compatibility for the case bitmask is set somewhere before the "if (sq_attr->rl_update)".

With best regards,
Slava


> +		MLX5_SET(sqc, sq_ctx, packet_pacing_rate_limit_index,
> +			 sq_attr->packet_pacing_rate_limit_index);
> +	}
>  	ret = mlx5_glue->devx_obj_modify(sq->obj, in, sizeof(in),
>  					 out, sizeof(out));
>  	if (ret) {
> diff --git a/drivers/common/mlx5/mlx5_devx_cmds.h
> b/drivers/common/mlx5/mlx5_devx_cmds.h
> index 930ae2c072..82d949972b 100644
> --- a/drivers/common/mlx5/mlx5_devx_cmds.h
> +++ b/drivers/common/mlx5/mlx5_devx_cmds.h
> @@ -519,6 +519,9 @@ struct mlx5_devx_modify_sq_attr {
>  	uint32_t state:4;
>  	uint32_t hairpin_peer_rq:24;
>  	uint32_t hairpin_peer_vhca:16;
> +	uint32_t rl_update:1;
> +	/* Set to update packet_pacing_rate_limit_index on a live SQ. */
> +	uint32_t packet_pacing_rate_limit_index:16;
>  };
> 
> 
> --
> 2.43.0