.. BSD LICENSE Copyright(c) 2015-2016 Intel Corporation. All rights reserved. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Intel Corporation nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. FM10K Poll Mode Driver ====================== The FM10K poll mode driver library provides support for the Intel FM10000 (FM10K) family of 40GbE/100GbE adapters. FTAG Based Forwarding of FM10K ------------------------------ FTAG Based Forwarding is a unique feature of FM10K. The FM10K family of NICs support the addition of a Fabric Tag (FTAG) to carry special information. The FTAG is placed at the beginning of the frame, it contains information such as where the packet comes from and goes, and the vlan tag. In FTAG based forwarding mode, the switch logic forwards packets according to glort (global resource tag) information, rather than the mac and vlan table. Currently this feature works only on PF. To enable this feature, the user should pass a devargs parameter to the eal like "-w 84:00.0,enable_ftag=1", and the application should make sure an appropriate FTAG is inserted for every frame on TX side. Vector PMD for FM10K -------------------- Vector PMD (vPMD) uses IntelĀ® SIMD instructions to optimize packet I/O. It improves load/store bandwidth efficiency of L1 data cache by using a wider SSE/AVX ''register (1)''. The wider register gives space to hold multiple packet buffers so as to save on the number of instructions when bulk processing packets. There is no change to the PMD API. The RX/TX handlers are the only two entries for vPMD packet I/O. They are transparently registered at runtime RX/TX execution if all required conditions are met. 1. To date, only an SSE version of FM10K vPMD is available. To ensure that vPMD is in the binary code, set ``CONFIG_RTE_LIBRTE_FM10K_INC_VECTOR=y`` in the configure file. Some constraints apply as pre-conditions for specific optimizations on bulk packet transfers. The following sections explain RX and TX constraints in the vPMD. RX Constraints ~~~~~~~~~~~~~~ Prerequisites and Pre-conditions ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ For Vector RX it is assumed that the number of descriptor rings will be a power of 2. With this pre-condition, the ring pointer can easily scroll back to the head after hitting the tail without a conditional check. In addition Vector RX can use this assumption to do a bit mask using ``ring_size - 1``. Features not Supported by Vector RX PMD ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Some features are not supported when trying to increase the throughput in vPMD. They are: * IEEE1588 * Flow director * Header split * RX checksum offload Other features are supported using optional MACRO configuration. They include: * HW VLAN strip * L3/L4 packet type To enable via ``RX_OLFLAGS`` use ``RTE_LIBRTE_FM10K_RX_OLFLAGS_ENABLE=y``. To guarantee the constraint, the following configuration flags in ``dev_conf.rxmode`` will be checked: * ``hw_vlan_extend`` * ``hw_ip_checksum`` * ``header_split`` * ``fdir_conf->mode`` RX Burst Size ^^^^^^^^^^^^^ As vPMD is focused on high throughput, it processes 4 packets at a time. So it assumes that the RX burst should be greater than 4 packets per burst. It returns zero if using ``nb_pkt`` < 4 in the receive handler. If ``nb_pkt`` is not a multiple of 4, a floor alignment will be applied. TX Constraint ~~~~~~~~~~~~~ Features not Supported by TX Vector PMD ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TX vPMD only works when ``txq_flags`` is set to ``FM10K_SIMPLE_TX_FLAG``. This means that it does not support TX multi-segment, VLAN offload or TX csum offload. The following MACROs are used for these three features: * ``ETH_TXQ_FLAGS_NOMULTSEGS`` * ``ETH_TXQ_FLAGS_NOVLANOFFL`` * ``ETH_TXQ_FLAGS_NOXSUMSCTP`` * ``ETH_TXQ_FLAGS_NOXSUMUDP`` * ``ETH_TXQ_FLAGS_NOXSUMTCP`` Limitations ----------- Switch manager ~~~~~~~~~~~~~~ The Intel FM10000 family of NICs integrate a hardware switch and multiple host interfaces. The FM10000 PMD driver only manages host interfaces. For the switch component another switch driver has to be loaded prior to to the FM10000 PMD driver. The switch driver can be acquired from Intel support. Only Testpoint is validated with DPDK, the latest version that has been validated with DPDK is 4.1.6. CRC striping ~~~~~~~~~~~~ The FM10000 family of NICs strip the CRC for every packets coming into the host interface. So, CRC will be stripped even when the ``rxmode.hw_strip_crc`` member is set to 0 in ``struct rte_eth_conf``. Maximum packet length ~~~~~~~~~~~~~~~~~~~~~ The FM10000 family of NICS support a maximum of a 15K jumbo frame. The value is fixed and cannot be changed. So, even when the ``rxmode.max_rx_pkt_len`` member of ``struct rte_eth_conf`` is set to a value lower than 15364, frames up to 15364 bytes can still reach the host interface. Statistic Polling Frequency ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The FM10000 NICs expose a set of statistics via the PCI BARs. These statistics are read from the hardware registers when ``rte_eth_stats_get()`` or ``rte_eth_xstats_get()`` is called. The packet counting registers are 32 bits while the byte counting registers are 48 bits. As a result, the statistics must be polled regularly in order to ensure the consistency of the returned reads. Given the PCIe Gen3 x8, about 50Gbps of traffic can occur. With 64 byte packets this gives almost 100 million packets/second, causing 32 bit integer overflow after approx 40 seconds. To ensure these overflows are detected and accounted for in the statistics, it is necessary to read statistic regularly. It is suggested to read stats every 20 seconds, which will ensure the statistics are accurate. Interrupt mode ~~~~~~~~~~~~~~ The FM10000 family of NICS need one separate interrupt for mailbox. So only drivers which support multiple interrupt vectors e.g. vfio-pci can work for fm10k interrupt mode.