Wire rte_eth_set_queue_rate_limit() to the mlx5 PMD. The callback allocates a per-queue PP index with the requested data rate, then modifies the live SQ via modify_bitmask bit 0 to apply the new packet_pacing_rate_limit_index — no queue teardown required.
Setting tx_rate=0 clears the PP index on the SQ and frees it. Capability check uses hca_attr.qos.packet_pacing directly (not dev_cap.txpp_en which requires Clock Queue prerequisites). This allows per-queue rate limiting without the tx_pp devarg. The callback rejects hairpin queues and queues whose SQ is not yet created. testpmd usage (no testpmd changes needed): set port 0 queue 0 rate 1000 set port 0 queue 1 rate 5000 set port 0 queue 0 rate 0 # disable Supported hardware: - ConnectX-6 Dx: full support, per-SQ rate via HW rate table - ConnectX-7/8: full support, coexists with wait-on-time scheduling - BlueField-2/3: full support as DPU rep ports Not supported: - ConnectX-5: packet_pacing exists but dynamic SQ modify may not work on all firmware versions - ConnectX-4 Lx and earlier: no packet_pacing capability Signed-off-by: Vincent Jardin <[email protected]> --- doc/guides/nics/features/mlx5.ini | 1 + doc/guides/nics/mlx5.rst | 54 ++++++++++++++ drivers/net/mlx5/mlx5.c | 2 + drivers/net/mlx5/mlx5_tx.h | 2 + drivers/net/mlx5/mlx5_txq.c | 118 ++++++++++++++++++++++++++++++ 5 files changed, 177 insertions(+) diff --git a/doc/guides/nics/features/mlx5.ini b/doc/guides/nics/features/mlx5.ini index 4f9c4c309b..3b3eda28b8 100644 --- a/doc/guides/nics/features/mlx5.ini +++ b/doc/guides/nics/features/mlx5.ini @@ -30,6 +30,7 @@ Inner RSS = Y SR-IOV = Y VLAN filter = Y Flow control = Y +Rate limitation = Y CRC offload = Y VLAN offload = Y L3 checksum offload = Y diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index 6bb8c07353..c72a60f084 100644 --- a/doc/guides/nics/mlx5.rst +++ b/doc/guides/nics/mlx5.rst @@ -580,6 +580,60 @@ for an additional list of options shared with other mlx5 drivers. (with ``tx_pp``) and ConnectX-7+ (wait-on-time) scheduling modes. The default value is zero. +.. _mlx5_per_queue_rate_limit: + +Per-Queue Tx Rate Limiting +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The mlx5 PMD supports per-queue Tx rate limiting via the standard ethdev +API ``rte_eth_set_queue_rate_limit()`` and ``rte_eth_get_queue_rate_limit()``. + +This feature uses the hardware packet pacing mechanism to enforce a data +rate on individual TX queues without tearing down the queue. The rate is +specified in Mbps. + +**Requirements:** + +- ConnectX-6 Dx or later with ``packet_pacing`` HCA capability. +- The DevX path must be used (default). The legacy Verbs path + (``dv_flow_en=0``) does not support dynamic SQ modification and + returns ``-EINVAL``. +- The queue must be started (SQ in RDY state) before setting a rate. + +**Supported hardware:** + +- ConnectX-6 Dx: per-SQ rate via HW rate table. +- ConnectX-7/8: full support, coexists with wait-on-time scheduling. +- BlueField-2/3: full support as DPU rep ports. + +**Not supported:** + +- ConnectX-5: ``packet_pacing`` exists but dynamic SQ modify may not + work on all firmware versions. +- ConnectX-4 Lx and earlier: no ``packet_pacing`` capability. + +**Rate table sharing:** + +The hardware rate table has a limited number of entries (typically 128 on +ConnectX-6 Dx). When multiple queues are configured with identical rate +parameters, the kernel mlx5 driver shares a single rate table entry across +them. Each queue still has its own independent SQ and enforces the rate +independently — queues are never merged. The rate cap applies per-queue: +if two queues share the same 1000 Mbps entry, each can send up to +1000 Mbps independently, they do not share a combined budget. + +This sharing is transparent and only affects table capacity: 128 entries +can serve thousands of queues as long as many use the same rate. Queues +with different rates consume separate entries. + +**Usage with testpmd:** + +.. code-block:: console + + testpmd> set port 0 queue 0 rate 1000 + testpmd> show port 0 queue 0 rate + testpmd> set port 0 queue 0 rate 0 + - ``tx_vec_en`` parameter [int] A nonzero value enables Tx vector with ConnectX-5 NICs and above. diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c index e795948187..e718f0fa8c 100644 --- a/drivers/net/mlx5/mlx5.c +++ b/drivers/net/mlx5/mlx5.c @@ -2621,6 +2621,7 @@ const struct eth_dev_ops mlx5_dev_ops = { .map_aggr_tx_affinity = mlx5_map_aggr_tx_affinity, .rx_metadata_negotiate = mlx5_flow_rx_metadata_negotiate, .get_restore_flags = mlx5_get_restore_flags, + .set_queue_rate_limit = mlx5_set_queue_rate_limit, }; /* Available operations from secondary process. */ @@ -2714,6 +2715,7 @@ const struct eth_dev_ops mlx5_dev_ops_isolate = { .count_aggr_ports = mlx5_count_aggr_ports, .map_aggr_tx_affinity = mlx5_map_aggr_tx_affinity, .get_restore_flags = mlx5_get_restore_flags, + .set_queue_rate_limit = mlx5_set_queue_rate_limit, }; /** diff --git a/drivers/net/mlx5/mlx5_tx.h b/drivers/net/mlx5/mlx5_tx.h index 51f330454a..975ff57acd 100644 --- a/drivers/net/mlx5/mlx5_tx.h +++ b/drivers/net/mlx5/mlx5_tx.h @@ -222,6 +222,8 @@ struct mlx5_txq_ctrl *mlx5_txq_get(struct rte_eth_dev *dev, uint16_t idx); int mlx5_txq_release(struct rte_eth_dev *dev, uint16_t idx); int mlx5_txq_releasable(struct rte_eth_dev *dev, uint16_t idx); int mlx5_txq_verify(struct rte_eth_dev *dev); +int mlx5_set_queue_rate_limit(struct rte_eth_dev *dev, uint16_t queue_idx, + uint32_t tx_rate); int mlx5_txq_get_sqn(struct mlx5_txq_ctrl *txq); void mlx5_txq_alloc_elts(struct mlx5_txq_ctrl *txq_ctrl); void mlx5_txq_free_elts(struct mlx5_txq_ctrl *txq_ctrl); diff --git a/drivers/net/mlx5/mlx5_txq.c b/drivers/net/mlx5/mlx5_txq.c index 3356c89758..ce08363ca9 100644 --- a/drivers/net/mlx5/mlx5_txq.c +++ b/drivers/net/mlx5/mlx5_txq.c @@ -1363,6 +1363,124 @@ mlx5_txq_release(struct rte_eth_dev *dev, uint16_t idx) return 0; } +/** + * Set per-queue packet pacing rate limit. + * + * @param dev + * Pointer to Ethernet device. + * @param queue_idx + * TX queue index. + * @param tx_rate + * TX rate in Mbps, 0 to disable rate limiting. + * + * @return + * 0 on success, a negative errno value otherwise and rte_errno is set. + */ +int +mlx5_set_queue_rate_limit(struct rte_eth_dev *dev, uint16_t queue_idx, + uint32_t tx_rate) +{ + struct mlx5_priv *priv = dev->data->dev_private; + struct mlx5_dev_ctx_shared *sh = priv->sh; + struct mlx5_txq_ctrl *txq_ctrl; + struct mlx5_devx_obj *sq_devx; + struct mlx5_devx_modify_sq_attr sq_attr = { 0 }; + struct mlx5_txq_rate_limit new_rate_limit = { 0 }; + int ret; + + if (!sh->cdev->config.hca_attr.qos.packet_pacing) { + DRV_LOG(ERR, "Port %u packet pacing not supported.", + dev->data->port_id); + rte_errno = ENOTSUP; + return -rte_errno; + } + if (priv->txqs == NULL || (*priv->txqs)[queue_idx] == NULL) { + DRV_LOG(ERR, "Port %u Tx queue %u not configured.", + dev->data->port_id, queue_idx); + rte_errno = EINVAL; + return -rte_errno; + } + txq_ctrl = container_of((*priv->txqs)[queue_idx], + struct mlx5_txq_ctrl, txq); + if (txq_ctrl->is_hairpin) { + DRV_LOG(ERR, "Port %u Tx queue %u is hairpin.", + dev->data->port_id, queue_idx); + rte_errno = EINVAL; + return -rte_errno; + } + if (txq_ctrl->obj == NULL) { + DRV_LOG(ERR, "Port %u Tx queue %u not initialized.", + dev->data->port_id, queue_idx); + rte_errno = EINVAL; + return -rte_errno; + } + /* + * For non-hairpin queues the SQ DevX object lives in + * obj->sq_obj.sq (used by DevX/HWS mode), while hairpin + * queues use obj->sq directly. These are different members + * of a union inside mlx5_txq_obj. + */ + sq_devx = txq_ctrl->obj->sq_obj.sq; + if (sq_devx == NULL) { + DRV_LOG(ERR, "Port %u Tx queue %u SQ not ready.", + dev->data->port_id, queue_idx); + rte_errno = EINVAL; + return -rte_errno; + } + if (dev->data->tx_queue_state[queue_idx] != + RTE_ETH_QUEUE_STATE_STARTED) { + DRV_LOG(ERR, + "Port %u Tx queue %u is not started, stop traffic before setting rate.", + dev->data->port_id, queue_idx); + rte_errno = EINVAL; + return -rte_errno; + } + if (tx_rate == 0) { + /* Disable rate limiting. */ + if (txq_ctrl->rate_limit.pp_id == 0) + return 0; /* Already disabled. */ + sq_attr.sq_state = MLX5_SQC_STATE_RDY; + sq_attr.state = MLX5_SQC_STATE_RDY; + sq_attr.rl_update = 1; + sq_attr.packet_pacing_rate_limit_index = 0; + ret = mlx5_devx_cmd_modify_sq(sq_devx, &sq_attr); + if (ret) { + DRV_LOG(ERR, + "Port %u Tx queue %u failed to clear rate.", + dev->data->port_id, queue_idx); + rte_errno = -ret; + return ret; + } + mlx5_txq_free_pp_rate_limit(&txq_ctrl->rate_limit); + DRV_LOG(DEBUG, "Port %u Tx queue %u rate limit disabled.", + dev->data->port_id, queue_idx); + return 0; + } + /* Allocate a new PP index for the requested rate into a temp. */ + ret = mlx5_txq_alloc_pp_rate_limit(sh, &new_rate_limit, tx_rate); + if (ret) + return ret; + /* Modify live SQ to use the new PP index. */ + sq_attr.sq_state = MLX5_SQC_STATE_RDY; + sq_attr.state = MLX5_SQC_STATE_RDY; + sq_attr.rl_update = 1; + sq_attr.packet_pacing_rate_limit_index = new_rate_limit.pp_id; + ret = mlx5_devx_cmd_modify_sq(sq_devx, &sq_attr); + if (ret) { + DRV_LOG(ERR, "Port %u Tx queue %u failed to set rate %u Mbps.", + dev->data->port_id, queue_idx, tx_rate); + mlx5_txq_free_pp_rate_limit(&new_rate_limit); + rte_errno = -ret; + return ret; + } + /* SQ updated — release old PP context, install new one. */ + mlx5_txq_free_pp_rate_limit(&txq_ctrl->rate_limit); + txq_ctrl->rate_limit = new_rate_limit; + DRV_LOG(DEBUG, "Port %u Tx queue %u rate set to %u Mbps (PP idx %u).", + dev->data->port_id, queue_idx, tx_rate, txq_ctrl->rate_limit.pp_id); + return 0; +} + /** * Verify if the queue can be released. * -- 2.43.0
