110 lines
3.2 KiB
ReStructuredText
110 lines
3.2 KiB
ReStructuredText
.. _8021Qav:
|
|
|
|
IEEE 802.1Qav
|
|
#############
|
|
|
|
Overview
|
|
********
|
|
|
|
Credit-based shaping is an alternative scheduling algorithm used in
|
|
network schedulers to achieve fairness when sharing a limited network
|
|
resource. Zephyr has support for configuring a credit-based shaper
|
|
described in the `IEEE 802.1Qav-2009 standard`_. Zephyr does not
|
|
implement the actual shaper; it only provides a way to configure the
|
|
shaper implemented by the Ethernet device driver.
|
|
|
|
Enabling 802.1Qav
|
|
*****************
|
|
|
|
To enable 802.1Qav shaper, the Ethernet device driver must declare
|
|
that it supports credit-based shaping. The Ethernet driver's capability
|
|
function must return ``ETHERNET_QAV`` value for this purpose. Typically
|
|
also priority queues ``ETHERNET_PRIORITY_QUEUES`` need to be supported.
|
|
|
|
.. code-block:: none
|
|
|
|
static enum ethernet_hw_caps eth_get_capabilities(const struct device *dev)
|
|
{
|
|
ARG_UNUSED(dev);
|
|
|
|
return ETHERNET_QAV | ETHERNET_PRIORITY_QUEUES |
|
|
ETHERNET_HW_VLAN | ETHERNET_LINK_10BASE_T |
|
|
ETHERNET_LINK_100BASE_T;
|
|
}
|
|
|
|
See ``sam-e70-xplained`` board Ethernet driver
|
|
:zephyr_file:`drivers/ethernet/eth_sam_gmac.c` for an example.
|
|
|
|
Configuring 802.1Qav
|
|
********************
|
|
|
|
The application can configure the credit-based shaper like this:
|
|
|
|
.. code-block:: c
|
|
|
|
#include <net/net_if.h>
|
|
#include <net/ethernet.h>
|
|
#include <net/ethernet_mgmt.h>
|
|
|
|
static void qav_set_status(struct net_if *iface,
|
|
int queue_id, bool enable)
|
|
{
|
|
struct ethernet_req_params params;
|
|
int ret;
|
|
|
|
memset(¶ms, 0, sizeof(params));
|
|
|
|
params.qav_param.queue_id = queue_id;
|
|
params.qav_param.enabled = enable;
|
|
params.qav_param.type = ETHERNET_QAV_PARAM_TYPE_STATUS;
|
|
|
|
/* Disable or enable Qav for a queue */
|
|
ret = net_mgmt(NET_REQUEST_ETHERNET_SET_QAV_PARAM,
|
|
iface, ¶ms,
|
|
sizeof(struct ethernet_req_params));
|
|
if (ret) {
|
|
LOG_ERR("Cannot %s Qav for queue %d for interface %p",
|
|
enable ? "enable" : "disable",
|
|
queue_id, iface);
|
|
}
|
|
}
|
|
|
|
static void qav_set_bandwidth_and_slope(struct net_if *iface,
|
|
int queue_id,
|
|
unsigned int bandwidth,
|
|
unsigned int idle_slope)
|
|
{
|
|
struct ethernet_req_params params;
|
|
int ret;
|
|
|
|
memset(¶ms, 0, sizeof(params));
|
|
|
|
params.qav_param.queue_id = queue_id;
|
|
params.qav_param.delta_bandwidth = bandwidth;
|
|
params.qav_param.type = ETHERNET_QAV_PARAM_TYPE_DELTA_BANDWIDTH;
|
|
|
|
ret = net_mgmt(NET_REQUEST_ETHERNET_SET_QAV_PARAM,
|
|
iface, ¶ms,
|
|
sizeof(struct ethernet_req_params));
|
|
if (ret) {
|
|
LOG_ERR("Cannot set Qav delta bandwidth %u for "
|
|
"queue %d for interface %p",
|
|
bandwidth, queue_id, iface);
|
|
}
|
|
|
|
params.qav_param.idle_slope = idle_slope;
|
|
params.qav_param.type = ETHERNET_QAV_PARAM_TYPE_IDLE_SLOPE;
|
|
|
|
ret = net_mgmt(NET_REQUEST_ETHERNET_SET_QAV_PARAM,
|
|
iface, ¶ms,
|
|
sizeof(struct ethernet_req_params));
|
|
if (ret) {
|
|
LOG_ERR("Cannot set Qav idle slope %u for "
|
|
"queue %d for interface %p",
|
|
idle_slope, queue_id, iface);
|
|
}
|
|
}
|
|
|
|
.. _IEEE 802.1Qav-2009 standard:
|
|
https://standards.ieee.org/standard/802_1Qav-2009.html
|