[dpdk-dev,v6,1/3] ethdev: new API to free consumed buffers in Tx ring
Checks
Commit Message
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).
Please double check my python coding in conf.py and make sure I
implemented 'feature_str_len' properly.
Signed-off-by: Billy McFall <bmcfall@redhat.com>
---
doc/guides/conf.py | 7 +++++--
doc/guides/nics/features/default.ini | 4 +++-
doc/guides/prog_guide/mempool_lib.rst | 26 ++++++++++++++++++++++++++
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, 85 insertions(+), 4 deletions(-)
Comments
Hi Billy,
On Thu, 9 Mar 2017 15:51:17 -0500, Billy McFall <bmcfall@redhat.com> wrote:
> 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).
>
> Please double check my python coding in conf.py and make sure I
> implemented 'feature_str_len' properly.
>
> Signed-off-by: Billy McFall <bmcfall@redhat.com>
[...]
> diff --git a/doc/guides/prog_guide/mempool_lib.rst b/doc/guides/prog_guide/mempool_lib.rst
> index ffdc109..a117881 100644
> --- a/doc/guides/prog_guide/mempool_lib.rst
> +++ b/doc/guides/prog_guide/mempool_lib.rst
> @@ -132,6 +132,32 @@ These user-owned caches can be explicitly passed to ``rte_mempool_generic_put()`
> The ``rte_mempool_default_cache()`` call returns the default internal cache if any.
> In contrast to the default caches, user-owned caches can be used by non-EAL threads too.
>
> +In addition to a core's local cache, many of the drivers don't 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.
> +
> +* If an application is designed to make multiple runs, like a packet generator, and one run has completed.
> + The application may want to reset to a clean state.
> + In this case, it may want to call the ``rte_eth_tx_done_cleanup()`` API to request each destination interface it has
> + been using to release all of 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.
I'm not sure the mempool documentation is the proper place to document
this API. I'll suggest to move it in ethdev documentation (poll_mode_drv.rst).
You can keep a small paragraph in mempool lib, but keep in mind that
mempool is not necessarily a pool of mbuf (it can be any kind of object).
Thanks,
Olivier
2017-03-09 15:51, Billy McFall:
> @@ -3097,6 +3101,33 @@ rte_eth_tx_buffer(uint8_t port_id, uint16_t queue_id,
> }
>
> /**
> + * 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);
> +
> +/**
> * Configure a callback for buffered packets which cannot be sent
> *
> * Register a specific callback to be called when an attempt is made to send
>
Please move this function below the tx_buffer functions (it is currently
between rte_eth_tx_buffer and rte_eth_tx_buffer_set_err_callback).
On Wed, Mar 15, 2017 at 6:29 AM, Olivier Matz <olivier.matz@6wind.com>
wrote:
> Hi Billy,
>
> On Thu, 9 Mar 2017 15:51:17 -0500, Billy McFall <bmcfall@redhat.com>
> wrote:
> > 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).
> >
> > Please double check my python coding in conf.py and make sure I
> > implemented 'feature_str_len' properly.
> >
> > Signed-off-by: Billy McFall <bmcfall@redhat.com>
>
> [...]
>
> > diff --git a/doc/guides/prog_guide/mempool_lib.rst
> b/doc/guides/prog_guide/mempool_lib.rst
> > index ffdc109..a117881 100644
> > --- a/doc/guides/prog_guide/mempool_lib.rst
> > +++ b/doc/guides/prog_guide/mempool_lib.rst
> > @@ -132,6 +132,32 @@ These user-owned caches can be explicitly passed to
> ``rte_mempool_generic_put()`
> > The ``rte_mempool_default_cache()`` call returns the default internal
> cache if any.
> > In contrast to the default caches, user-owned caches can be used by
> non-EAL threads too.
> >
> > +In addition to a core's local cache, many of the drivers don't 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.
> > +
> > +* If an application is designed to make multiple runs, like a packet
> generator, and one run has completed.
> > + The application may want to reset to a clean state.
> > + In this case, it may want to call the ``rte_eth_tx_done_cleanup()``
> API to request each destination interface it has
> > + been using to release all of 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.
>
> I'm not sure the mempool documentation is the proper place to document
> this API. I'll suggest to move it in ethdev documentation
> (poll_mode_drv.rst).
>
> You can keep a small paragraph in mempool lib, but keep in mind that
> mempool is not necessarily a pool of mbuf (it can be any kind of object).
>
> Not sure this API needs to be documented in multiple places. I'll move the
content to the poll_mode_drv.rst file.
>
> Thanks,
> Olivier
>
> Billy
@@ -64,6 +64,9 @@
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)
@@ -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 =
@@ -132,6 +132,32 @@ These user-owned caches can be explicitly passed to ``rte_mempool_generic_put()`
The ``rte_mempool_default_cache()`` call returns the default internal cache if any.
In contrast to the default caches, user-owned caches can be used by non-EAL threads too.
+In addition to a core's local cache, many of the drivers don't 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.
+
+* If an application is designed to make multiple runs, like a packet generator, and one run has completed.
+ The application may want to reset to a clean state.
+ In this case, it may want to call the ``rte_eth_tx_done_cleanup()`` API to request each destination interface it has
+ been using to release all of 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.
+
+
Mempool Handlers
------------------------
@@ -41,11 +41,16 @@ New Features
Also, make sure to start the actual text at the margin.
=========================================================
-
* **Added powerpc support in pci probing for vfio-pci devices.**
sPAPR IOMMU based pci probing enabled for vfio-pci devices.
+* **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.
+
Resolved Issues
---------------
@@ -1259,6 +1259,20 @@ rte_eth_tx_buffer_set_err_callback(struct rte_eth_dev_tx_buffer *buffer,
}
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);
+}
+
+int
rte_eth_tx_buffer_init(struct rte_eth_dev_tx_buffer *buffer, uint16_t size)
{
int ret = 0;
@@ -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. */
@@ -3097,6 +3101,33 @@ rte_eth_tx_buffer(uint8_t port_id, uint16_t queue_id,
}
/**
+ * 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);
+
+/**
* Configure a callback for buffered packets which cannot be sent
*
* Register a specific callback to be called when an attempt is made to send