mlx5dv_sched_node[/leaf]_mlx5dv_schedanode[/leaf]acreate / modify / destroy(3)
NAME
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
SYNOPSIS
#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);
DESCRIPTION
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 enti-
ties. 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.
ARGUMENTS
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 ele-
ments 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 in-
dicates 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.
NOTES
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);
RETURN VALUE
Upon success *mlx5dv_sched_node[/leaf]_create()* will return a new
struct mlx5dv_sched_node[/leaf], on error NULL will be returned and er-
rno will be set.
Upon success modify and destroy, 0 is returned or the value of errno on
a failure.
SEE ALSO
ibv_create_qp_ex(3), mlx5dv_modify_qp_sched_elem(3)
AUTHOR
Mark Zhang <markzhang@nvidia.com>
Ariel Almog <ariela@nvidia.com>
mlx5 mlx5dv_sched2node[/leaf]_create / modify / destroy(3)
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