501945eec0
The RX_OLFLAGS option was renamed from DISABLE to ENABLE in driver code
and linux config.
It is now renamed also in bsd config and documentation.
Fixes: 359f106a69a9 ("ixgbe: prefer enabling olflags rather than not disabling")
Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
181 lines
5.9 KiB
ReStructuredText
181 lines
5.9 KiB
ReStructuredText
.. BSD LICENSE
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Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of Intel Corporation nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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IXGBE Driver
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============
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Vector PMD for IXGBE
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--------------------
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Vector PMD uses Intel® SIMD instructions to optimize packet I/O.
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It improves load/store bandwidth efficiency of L1 data cache by using a wider SSE/AVX register 1 (1).
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The wider register gives space to hold multiple packet buffers so as to save instruction number when processing bulk of packets.
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There is no change to PMD API. The RX/TX handler are the only two entries for vPMD packet I/O.
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They are transparently registered at runtime RX/TX execution if all condition checks pass.
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1. To date, only an SSE version of IX GBE vPMD is available.
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To ensure that vPMD is in the binary code, ensure that the option CONFIG_RTE_IXGBE_INC_VECTOR=y is in the configure file.
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Some constraints apply as pre-conditions for specific optimizations on bulk packet transfers.
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The following sections explain RX and TX constraints in the vPMD.
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RX Constraints
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~~~~~~~~~~~~~~
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Prerequisites and Pre-conditions
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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The following prerequisites apply:
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* To enable vPMD to work for RX, bulk allocation for Rx must be allowed.
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Ensure that the following pre-conditions are satisfied:
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* rxq->rx_free_thresh >= RTE_PMD_IXGBE_RX_MAX_BURST
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* rxq->rx_free_thresh < rxq->nb_rx_desc
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* (rxq->nb_rx_desc % rxq->rx_free_thresh) == 0
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* rxq->nb_rx_desc < (IXGBE_MAX_RING_DESC - RTE_PMD_IXGBE_RX_MAX_BURST)
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These conditions are checked in the code.
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Scattered packets are not supported in this mode.
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If an incoming packet is greater than the maximum acceptable length of one "mbuf" data size (by default, the size is 2 KB),
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vPMD for RX would be disabled.
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By default, IXGBE_MAX_RING_DESC is set to 4096 and RTE_PMD_IXGBE_RX_MAX_BURST is set to 32.
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Feature not Supported by RX Vector PMD
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Some features are not supported when trying to increase the throughput in vPMD.
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They are:
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* IEEE1588
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* FDIR
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* Header split
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* RX checksum off load
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Other features are supported using optional MACRO configuration. They include:
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* HW VLAN strip
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* HW extend dual VLAN
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* Enabled by RX_OLFLAGS (RTE_IXGBE_RX_OLFLAGS_ENABLE=y)
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To guarantee the constraint, configuration flags in dev_conf.rxmode will be checked:
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* hw_vlan_strip
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* hw_vlan_extend
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* hw_ip_checksum
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* header_split
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* dev_conf
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fdir_conf->mode will also be checked.
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RX Burst Size
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^^^^^^^^^^^^^
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As vPMD is focused on high throughput, it assumes that the RX burst size is equal to or greater than 32 per burst.
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It returns zero if using nb_pkt < 32 as the expected packet number in the receive handler.
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TX Constraint
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~~~~~~~~~~~~~
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Prerequisite
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^^^^^^^^^^^^
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The only prerequisite is related to tx_rs_thresh.
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The tx_rs_thresh value must be greater than or equal to RTE_PMD_IXGBE_TX_MAX_BURST,
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but less or equal to RTE_IXGBE_TX_MAX_FREE_BUF_SZ.
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Consequently, by default the tx_rs_thresh value is in the range 32 to 64.
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Feature not Supported by RX Vector PMD
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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TX vPMD only works when txq_flags is set to IXGBE_SIMPLE_FLAGS.
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This means that it does not support TX multi-segment, VLAN offload and TX csum offload.
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The following MACROs are used for these three features:
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* ETH_TXQ_FLAGS_NOMULTSEGS
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* ETH_TXQ_FLAGS_NOVLANOFFL
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* ETH_TXQ_FLAGS_NOXSUMSCTP
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* ETH_TXQ_FLAGS_NOXSUMUDP
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* ETH_TXQ_FLAGS_NOXSUMTCP
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Sample Application Notes
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~~~~~~~~~~~~~~~~~~~~~~~~
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testpmd
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^^^^^^^
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By default, using CONFIG_RTE_IXGBE_RX_OLFLAGS_ENABLE=y:
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.. code-block:: console
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./x86_64-native-linuxapp-gcc/app/testpmd -c 300 -n 4 -- -i --burst=32 --rxfreet=32 --mbcache=250 --txpt=32 --rxht=8 --rxwt=0 --txfreet=32 --txrst=32 --txqflags=0xf01
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When CONFIG_RTE_IXGBE_RX_OLFLAGS_ENABLE=n, better performance can be achieved:
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.. code-block:: console
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./x86_64-native-linuxapp-gcc/app/testpmd -c 300 -n 4 -- -i --burst=32 --rxfreet=32 --mbcache=250 --txpt=32 --rxht=8 --rxwt=0 --txfreet=32 --txrst=32 --txqflags=0xf01 --disable-hw-vlan
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l3fwd
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^^^^^
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When running l3fwd with vPMD, there is one thing to note.
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In the configuration, ensure that port_conf.rxmode.hw_ip_checksum=0.
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Otherwise, by default, RX vPMD is disabled.
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load_balancer
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^^^^^^^^^^^^^
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As in the case of l3fwd, set configure port_conf.rxmode.hw_ip_checksum=0 to enable vPMD.
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In addition, for improved performance, use -bsz "(32,32),(64,64),(32,32)" in load_balancer to avoid using the default burst size of 144.
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