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NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | NOTES | RETURN VALUE | SEE ALSO | AUTHOR | COLOPHON |
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mlx5dv_sc.../ destroy(3) mlx5 Programmer’s Manualmlx5dv_sc.../ destroy(3)
mlx5dv_sched_node_create - Creates a scheduling node element
mlx5dv_sched_leaf_create - Creates a scheduling leaf element
mlx5dv_sched_node_modify - Modifies a node scheduling element
mlx5dv_sched_leaf_modify - Modifies a leaf scheduling element
mlx5dv_sched_node_destroy - Destroys a node scheduling element
mlx5dv_sched_leaf_destroy - Destroys a leaf scheduling element
#include <infiniband/mlx5dv.h>
struct mlx5dv_sched_node *mlx5dv_sched_node_create(struct ibv_context *context,
struct mlx5dv_sched_attr *sched_attr);
struct mlx5dv_sched_leaf *mlx5dv_sched_leaf_create(struct ibv_context *context,
struct mlx5dv_sched_attr *sched_attr);
int mlx5dv_sched_node_modify(struct mlx5dv_sched_node *node,
struct mlx5dv_sched_attr *sched_attr);
int mlx5dv_sched_leaf_modify(struct mlx5dv_sched_leaf *leaf,
struct mlx5dv_sched_attr *sched_attr);
int mlx5dv_sched_node_destroy(struct mlx5dv_sched_node *node);
int mlx5dv_sched_leaf_destroy(struct mlx5dv_sched_leaf *leaf);
The transmit scheduling element (SE) is scheduling the
transmission for of all nodes connected it. By configuring the
SE, QoS policies may be enforced between the competing entities
(e.g. SQ, QP).
In each scheduling cycle, the SE schedules all ready-to-transmit
entities. The SE assures that weight for each entity is met. If
entity has reached its maximum allowed bandwidth within the
scheduling cycle, it won’t be scheduled till end of the scheduling
cycle. The unused transmission bandwidth will be distributed
among the remaining entities assuring the weight setting.
The SEs are connected in a tree structure. The entity is
connected to a leaf. One or more leaves can be connected to a SE
node. One or more SE nodes can be connected to a SE node, until
reaching the SE root. For each input on each node, user can
assign the maximum bandwidth and the scheduling weight.
The SE APIs (mlx5dv_sched_*) allows access by verbs application to
set the hierarchical SE tree to the device. The ibv_qp shall be
connected to a leaf.
Please see ibv_create_qp_ex(3) man page for context.
mlx5dv_sched_attr
struct mlx5dv_sched_attr {
struct mlx5dv_sched_node *parent;
uint32_t flags;
uint32_t bw_share;
uint32_t max_avg_bw;
uint64_t comp_mask;
};
parent A node handler to the parent scheduling element which this
scheduling element will be connected to. The root
scheduling element doesn’t have a parent.
flags Specifying what attributes in the structure are valid:
MLX5DV_SCHED_ELEM_ATTR_FLAGS_BW_SHARE for bw_share
MLX5DV_SCHED_ELEM_ATTR_FLAGS_MAX_AVG_BW for max_avg_bw
bw_share
The relative bandwidth share allocated for this element.
This field has no units. The bandwidth is shared between
all elements connected to the same parent element,
relatively to their bw_share. Value of 0, indicates a
device default Weight. This field must be 0 for the root
TSAR.
max_avg_bw
The maximal transmission rate allowed for the element,
averaged over time. Value is given in units of 1
Mbit/sec. Value 0x0 indicates the rate is unlimited. This
field must be 0 for the root TSAR.
comp_mask
Reserved for future extension, must be 0 now.
node/leaf
For modify, destroy: the scheduling element to work on.
sched_attr
For create, modify: the attribute of the scheduling element
to work on.
For example if an application wants to create 2 QoS QP groups:
g1: 70% bandwidth share of this application
g2: 30% bandwidth share of this application, with maximum average bandwidth limited to 4Gbps
Pseudo code:
struct mlx5dv_sched_node *root;
struct mlx5dv_sched_leaf *leaf_g1, *leaf_g2;
struct mlx5dv_sched_attr;
struct ibv_qp *qp1, qp2;
/* Create root node */
attr.comp_mask = 0;
attr.parent = NULL;
attr.flags = 0;
root = mlx5dv_sched_node_create(context, attr);
/* Create group1 */
attr.comp_mask = 0;
attr.parent = root;
attr.bw_share = 7;
attr.flags = MLX5DV_SCHED_ELEM_ATTR_FLAGS_BW_SHARE;
leaf_g1 = mlx5dv_sched_leaf_create(context, attr);
/* Create group2 */
attr.comp_mask = 0;
attr.parent = root;
attr.bw_share = 3;
attr.max_avg_bw = 4096;
attr.flags = MLX5DV_SCHED_ELEM_ATTR_FLAGS_BW_SHARE | MLX5DV_SCHED_ELEM_ATTR_FLAGS_MAX_AVG_BW;
leaf_g2 = mlx5dv_sched_leaf_create(context, attr);
foreach (qp1 in group1)
mlx5dv_modify_qp_sched_elem(qp1, leaf_g1, NULL);
foreach (qp2 in group2)
mlx5dv_modify_qp_sched_elem(qp2, leaf_g2, NULL);
Upon success *mlx5dv_sched_node[/leaf]_create()* will return a new
struct mlx5dv_sched_node[/leaf], on error NULL will be returned
and errno will be set.
Upon success modify and destroy, 0 is returned or the value of
errno on a failure.
ibv_create_qp_ex(3), mlx5dv_modify_qp_sched_elem(3)
Mark Zhang ⟨markzhang@nvidia.com⟩
Ariel Almog ⟨ariela@nvidia.com⟩
This page is part of the rdma-core (RDMA Core Userspace Libraries
and Daemons) project. Information about the project can be found
at ⟨https://github.com/linux-rdma/rdma-core⟩. If you have a bug
report for this manual page, send it to
linux-rdma@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2025-08-11. (At
that time, the date of the most recent commit that was found in
the repository was 2025-08-04.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
mlx5 2020-9-3 mlx5dv_sc.../ destroy(3)
Pages that refer to this page: mlx5dv_modify_qp_sched_elem(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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