[PATCH v1 10/10] net/mlx5: add rate table capacity query API

Vincent Jardin
2026-03-10T09:22:52Z

Add rte_pmd_mlx5_pp_rate_table_query() to report the HW packet
pacing rate table size and how many entries are currently in use.

The total comes from the HCA QoS capability
packet_pacing_rate_table_size. The used count is derived by
collecting unique non-zero PP indices across all TX queues.

Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
drivers/net/mlx5/mlx5_tx.c | 51 +++++++++++++++++++++++++++++++++
drivers/net/mlx5/rte_pmd_mlx5.h | 27 +++++++++++++++++
2 files changed, 78 insertions(+)

diff --git a/drivers/net/mlx5/mlx5_tx.c b/drivers/net/mlx5/mlx5_tx.c
index 7051390a5e..4cd0e1ce60 100644
--- a/drivers/net/mlx5/mlx5_tx.c
+++ b/drivers/net/mlx5/mlx5_tx.c
@@ -886,3 +886,54 @@ int rte_pmd_mlx5_txq_rate_limit_query(uint16_t port_id, uint16_t queue_id,
packet_pacing_rate_limit_index);
return 0;
}
+
+RTE_EXPORT_EXPERIMENTAL_SYMBOL(rte_pmd_mlx5_pp_rate_table_query, 26.07)
+int rte_pmd_mlx5_pp_rate_table_query(uint16_t port_id,
+ struct rte_pmd_mlx5_pp_rate_table_info *info)
+{
+ struct rte_eth_dev *dev;
+ struct mlx5_priv *priv;
+ uint16_t used = 0;
+ uint16_t seen[RTE_MAX_QUEUES_PER_PORT];
+ unsigned int i;
+
+ if (info == NULL)
+ return -EINVAL;
+ if (!rte_eth_dev_is_valid_port(port_id))
+ return -ENODEV;
+ dev = &rte_eth_devices[port_id];
+ priv = dev->data->dev_private;
+ if (!priv->sh->cdev->config.hca_attr.qos.packet_pacing) {
+ rte_errno = ENOTSUP;
+ return -ENOTSUP;
+ }
+ info->total = priv->sh->cdev->config.hca_attr.qos
+ .packet_pacing_rate_table_size;
+ /* Count unique non-zero PP indices across all TX queues. */
+ for (i = 0; i < priv->txqs_n; i++) {
+ struct mlx5_txq_data *txq_data;
+ struct mlx5_txq_ctrl *txq_ctrl;
+ uint16_t pp_id;
+ uint16_t j;
+ bool dup;
+
+ if (priv->txqs == NULL || (*priv->txqs)[i] == NULL)
+ continue;
+ txq_data = (*priv->txqs)[i];
+ txq_ctrl = container_of(txq_data, struct mlx5_txq_ctrl, txq);
+ pp_id = txq_ctrl->rl.pp_id;
+ if (pp_id == 0)
+ continue;
+ dup = false;
+ for (j = 0; j < used; j++) {
+ if (seen[j] == pp_id) {
+ dup = true;
+ break;
+ }
+ }
+ if (!dup && used < RTE_DIM(seen))
+ seen[used++] = pp_id;
+ }
+ info->used = used;
+ return 0;
+}
diff --git a/drivers/net/mlx5/rte_pmd_mlx5.h b/drivers/net/mlx5/rte_pmd_mlx5.h
index 698d7d2032..4033b9acc7 100644
--- a/drivers/net/mlx5/rte_pmd_mlx5.h
+++ b/drivers/net/mlx5/rte_pmd_mlx5.h
@@ -450,6 +450,33 @@ int
rte_pmd_mlx5_txq_rate_limit_query(uint16_t port_id, uint16_t queue_id,
struct rte_pmd_mlx5_txq_rate_limit_info *info);

+/**
+ * Packet pacing rate table capacity information.
+ */
+struct rte_pmd_mlx5_pp_rate_table_info {
+ uint16_t total; /**< Total HW rate table entries. */
+ uint16_t used; /**< Currently allocated entries. */
+};
+
+/**
+ * Query packet pacing rate table capacity.
+ *
+ * @param[in] port_id
+ * Port ID.
+ * @param[out] info
+ * Rate table capacity information.
+ *
+ * @return
+ * 0 on success, negative errno on failure:
+ * - -ENODEV: invalid port_id.
+ * - -EINVAL: info is NULL.
+ * - -ENOTSUP: packet pacing not supported.
+ */
+__rte_experimental
+int
+rte_pmd_mlx5_pp_rate_table_query(uint16_t port_id,
+ struct rte_pmd_mlx5_pp_rate_table_info *info);
+
/** Type of mlx5 driver event for which custom callback is called. */
enum rte_pmd_mlx5_driver_event_cb_type {
/** Called after HW Rx queue is created. */
--
2.43.0