From 44a718c457b5f8f034e490a626a9b970a79436ee Mon Sep 17 00:00:00 2001 From: Billy McFall Date: Fri, 24 Mar 2017 14:55:53 -0400 Subject: [PATCH] ethdev: add API to free consumed buffers in Tx ring Add a new API to force free consumed buffers on Tx ring. API will return the number of packets freed (0-n) or error code if feature not supported (-ENOTSUP) or input invalid (-ENODEV). Signed-off-by: Billy McFall Acked-by: Keith Wiles --- doc/guides/conf.py | 7 +++-- doc/guides/nics/features/default.ini | 4 ++- doc/guides/prog_guide/poll_mode_drv.rst | 36 +++++++++++++++++++++++++ doc/guides/rel_notes/release_17_05.rst | 7 +++++ lib/librte_ether/rte_ethdev.c | 14 ++++++++++ lib/librte_ether/rte_ethdev.h | 31 +++++++++++++++++++++ 6 files changed, 96 insertions(+), 3 deletions(-) diff --git a/doc/guides/conf.py b/doc/guides/conf.py index 34c62de679..4cac26d5f0 100644 --- a/doc/guides/conf.py +++ b/doc/guides/conf.py @@ -64,6 +64,9 @@ release = version master_doc = 'index' +# Maximum feature description string length +feature_str_len = 25 + # Figures, tables and code-blocks automatically numbered if they have caption numfig = True @@ -300,7 +303,7 @@ def print_table_body(outfile, num_cols, ini_files, ini_data, default_features): def print_table_row(outfile, feature, line): """ Print a single row of the table with fixed formatting. """ line = line.rstrip() - print(' {:<20}{}'.format(feature, line), file=outfile) + print(' {:<{}}{}'.format(feature, feature_str_len, line), file=outfile) def print_table_divider(outfile, num_cols): @@ -309,7 +312,7 @@ def print_table_divider(outfile, num_cols): column_dividers = ['='] * num_cols line += ' '.join(column_dividers) - feature = '=' * 20 + feature = '=' * feature_str_len print_table_row(outfile, feature, line) diff --git a/doc/guides/nics/features/default.ini b/doc/guides/nics/features/default.ini index 299078f213..0135c0c4e5 100644 --- a/doc/guides/nics/features/default.ini +++ b/doc/guides/nics/features/default.ini @@ -3,7 +3,8 @@ ; ; This file defines the features that are valid for inclusion in ; the other driver files and also the order that they appear in -; the features table in the documentation. +; the features table in the documentation. The feature description +; string should not exceed feature_str_len defined in conf.py. ; [Features] Speed capabilities = @@ -11,6 +12,7 @@ Link status = Link status event = Queue status event = Rx interrupt = +Free Tx mbuf on demand = Queue start/stop = MTU update = Jumbo frame = diff --git a/doc/guides/prog_guide/poll_mode_drv.rst b/doc/guides/prog_guide/poll_mode_drv.rst index d4c92ea2cf..e48c121c00 100644 --- a/doc/guides/prog_guide/poll_mode_drv.rst +++ b/doc/guides/prog_guide/poll_mode_drv.rst @@ -249,6 +249,42 @@ One descriptor in the TX ring is used as a sentinel to avoid a hardware race con When configuring for DCB operation, at port initialization, both the number of transmit queues and the number of receive queues must be set to 128. +Free Tx mbuf on Demand +~~~~~~~~~~~~~~~~~~~~~~ + +Many of the drivers do not release the mbuf back to the mempool, or local cache, +immediately after the packet has been transmitted. +Instead, they leave the mbuf in their Tx ring and +either perform a bulk release when the ``tx_rs_thresh`` has been crossed +or free the mbuf when a slot in the Tx ring is needed. + +An application can request the driver to release used mbufs with the ``rte_eth_tx_done_cleanup()`` API. +This API requests the driver to release mbufs that are no longer in use, +independent of whether or not the ``tx_rs_thresh`` has been crossed. +There are two scenarios when an application may want the mbuf released immediately: + +* When a given packet needs to be sent to multiple destination interfaces + (either for Layer 2 flooding or Layer 3 multi-cast). + One option is to make a copy of the packet or a copy of the header portion that needs to be manipulated. + A second option is to transmit the packet and then poll the ``rte_eth_tx_done_cleanup()`` API + until the reference count on the packet is decremented. + Then the same packet can be transmitted to the next destination interface. + The application is still responsible for managing any packet manipulations needed + between the different destination interfaces, but a packet copy can be avoided. + This API is independent of whether the packet was transmitted or dropped, + only that the mbuf is no longer in use by the interface. + +* Some applications are designed to make multiple runs, like a packet generator. + For performance reasons and consistency between runs, + the application may want to reset back to an initial state + between each run, where all mbufs are returned to the mempool. + In this case, it can call the ``rte_eth_tx_done_cleanup()`` API + for each destination interface it has been using + to request it to release of all its used mbufs. + +To determine if a driver supports this API, check for the *Free Tx mbuf on demand* feature +in the *Network Interface Controller Drivers* document. + Hardware Offload ~~~~~~~~~~~~~~~~ diff --git a/doc/guides/rel_notes/release_17_05.rst b/doc/guides/rel_notes/release_17_05.rst index 918f483968..2a045b3e2f 100644 --- a/doc/guides/rel_notes/release_17_05.rst +++ b/doc/guides/rel_notes/release_17_05.rst @@ -41,6 +41,12 @@ New Features Also, make sure to start the actual text at the margin. ========================================================= +* **Added free Tx mbuf on demand API.** + + Added a new function ``rte_eth_tx_done_cleanup()`` which allows an application + to request the driver to release mbufs from their Tx ring that are no longer + in use, independent of whether or not the ``tx_rs_thresh`` has been crossed. + * **Increased number of next hops for LPM IPv6 to 2^21.** The next_hop field is extended from 8 bits to 21 bits for IPv6. @@ -49,6 +55,7 @@ New Features sPAPR IOMMU based pci probing enabled for vfio-pci devices. + Resolved Issues --------------- diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c index eb0a94a9ac..b796e7d5ea 100644 --- a/lib/librte_ether/rte_ethdev.c +++ b/lib/librte_ether/rte_ethdev.c @@ -1275,6 +1275,20 @@ rte_eth_tx_buffer_init(struct rte_eth_dev_tx_buffer *buffer, uint16_t size) return ret; } +int +rte_eth_tx_done_cleanup(uint8_t port_id, uint16_t queue_id, uint32_t free_cnt) +{ + struct rte_eth_dev *dev = &rte_eth_devices[port_id]; + + /* Validate Input Data. Bail if not valid or not supported. */ + RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); + RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_done_cleanup, -ENOTSUP); + + /* Call driver to free pending mbufs. */ + return (*dev->dev_ops->tx_done_cleanup)(dev->data->tx_queues[queue_id], + free_cnt); +} + void rte_eth_promiscuous_enable(uint8_t port_id) { diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h index 4be217cc95..b3ee8728b9 100644 --- a/lib/librte_ether/rte_ethdev.h +++ b/lib/librte_ether/rte_ethdev.h @@ -1183,6 +1183,9 @@ typedef int (*eth_fw_version_get_t)(struct rte_eth_dev *dev, char *fw_version, size_t fw_size); /**< @internal Get firmware information of an Ethernet device. */ +typedef int (*eth_tx_done_cleanup_t)(void *txq, uint32_t free_cnt); +/**< @internal Force mbufs to be from TX ring. */ + typedef void (*eth_rxq_info_get_t)(struct rte_eth_dev *dev, uint16_t rx_queue_id, struct rte_eth_rxq_info *qinfo); @@ -1488,6 +1491,7 @@ struct eth_dev_ops { eth_rx_disable_intr_t rx_queue_intr_disable; /**< Disable Rx queue interrupt. */ eth_tx_queue_setup_t tx_queue_setup;/**< Set up device TX queue. */ eth_queue_release_t tx_queue_release; /**< Release TX queue. */ + eth_tx_done_cleanup_t tx_done_cleanup;/**< Free tx ring mbufs */ eth_dev_led_on_t dev_led_on; /**< Turn on LED. */ eth_dev_led_off_t dev_led_off; /**< Turn off LED. */ @@ -3177,6 +3181,33 @@ void rte_eth_tx_buffer_count_callback(struct rte_mbuf **pkts, uint16_t unsent, void *userdata); +/** + * Request the driver to free mbufs currently cached by the driver. The + * driver will only free the mbuf if it is no longer in use. It is the + * application's responsibity to ensure rte_eth_tx_buffer_flush(..) is + * called if needed. + * + * @param port_id + * The port identifier of the Ethernet device. + * @param queue_id + * The index of the transmit queue through which output packets must be + * sent. + * The value must be in the range [0, nb_tx_queue - 1] previously supplied + * to rte_eth_dev_configure(). + * @param free_cnt + * Maximum number of packets to free. Use 0 to indicate all possible packets + * should be freed. Note that a packet may be using multiple mbufs. + * @return + * Failure: < 0 + * -ENODEV: Invalid interface + * -ENOTSUP: Driver does not support function + * Success: >= 0 + * 0-n: Number of packets freed. More packets may still remain in ring that + * are in use. + */ +int +rte_eth_tx_done_cleanup(uint8_t port_id, uint16_t queue_id, uint32_t free_cnt); + /** * The eth device event type for interrupt, and maybe others in the future. */ -- 2.20.1