Before this patch, implementation details and configuration of hairpin
queues were decided internally by the PMD. Applications had no control
over the configuration of Rx and Tx hairpin queues, despite number of
descriptors, explicit Tx flow mode and disabling automatic binding.
This patch addresses that by adding:
- Hairpin queue capabilities reported by PMDs.
- New configuration options for Rx and Tx hairpin queues.
Main goal of this patch is to allow applications to provide
configuration hints regarding placement of hairpin queues.
These hints specify whether buffers of hairpin queues should be placed
in host memory or in dedicated device memory. Different memory options
may have different performance characteristics and hairpin configuration
should be fine-tuned to the specific application and use case.
This patch introduces new hairpin queue configuration options through
rte_eth_hairpin_conf struct, allowing to tune Rx and Tx hairpin queues
memory configuration. Hairpin configuration is extended with the
following fields:
- use_locked_device_memory - If set, PMD will use specialized on-device
memory to store RX or TX hairpin queue data.
- use_rte_memory - If set, PMD will use DPDK-managed memory to store RX
or TX hairpin queue data.
- force_memory - If set, PMD will be forced to use provided memory
settings. If no appropriate resources are available, then device start
will fail. If unset and no resources are available, PMD will fallback
to using default type of resource for given queue.
If application chooses to use PMD default memory configuration, all of
these flags should remain unset.
Hairpin capabilities are also extended, to allow verification of support
of given hairpin memory configurations. Struct rte_eth_hairpin_cap is
extended with two additional fields of type rte_eth_hairpin_queue_cap:
- rx_cap - memory capabilities of hairpin RX queues.
- tx_cap - memory capabilities of hairpin TX queues.
Struct rte_eth_hairpin_queue_cap exposes whether given queue type
supports use_locked_device_memory and use_rte_memory flags.
Signed-off-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
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