1.. SPDX-License-Identifier: BSD-3-Clause 2 Copyright 2021 Mellanox Technologies, Ltd 3 4.. include:: <isonum.txt> 5 6MLX5 compress driver 7==================== 8 9The MLX5 compress driver library 10(**librte_compress_mlx5**) provides support for **Mellanox BlueField 2** 11families of 25/50/100/200 Gb/s adapters. 12 13Design 14------ 15 16This PMD is configuring the compress, decompress amd DMA engines. 17 18GGAs (Generic Global Accelerators) are offload engines that can be used 19to do memory to memory tasks on data. 20These engines are part of the ARM complex of the BlueField chip, and as 21such they do not use NIC related resources (e.g. RX/TX bandwidth). 22They do share the same PCI and memory bandwidth. 23 24So, using the BlueField device (starting from BlueField 2), the compress 25class operations can be supported in parallel to the net, vDPA and 26RegEx class operations. 27 28For security reasons and robustness, this driver only deals with virtual 29memory addresses. The way resources allocations are handled by the kernel, 30combined with hardware specifications that allow to handle virtual memory 31addresses directly, ensure that DPDK applications cannot access random 32physical memory (or memory that does not belong to the current process). 33 34The PMD uses libibverbs and libmlx5 to access the device firmware 35or directly the hardware components. 36There are different levels of objects and bypassing abilities 37to get the best performances: 38 39- Verbs is a complete high-level generic API. 40- Direct Verbs is a device-specific API. 41- DevX allows to access firmware objects. 42 43Enabling librte_compress_mlx5 causes DPDK applications to be linked against 44libibverbs. 45 46Mellanox mlx5 PCI device can be probed by number of different PCI devices, 47for example net / vDPA / RegEx. To select the compress PMD ``class=compress`` 48should be specified as device parameter. The compress device can be probed and 49used with other Mellanox classes, by adding more options in the class. 50For example: ``class=net:compress`` will probe both the net PMD and the compress 51PMD. 52 53Features 54-------- 55 56Compress mlx5 PMD has support for: 57 58Compression/Decompression algorithm: 59 60* DEFLATE. 61 62NULL algorithm for DMA operations. 63 64Huffman code type: 65 66* FIXED. 67* DYNAMIC. 68 69Window size support: 70 711KB, 2KB, 4KB, 8KB, 16KB and 32KB. 72 73Shareable transformation. 74 75Checksum generation: 76 77* CRC32, Adler32 and combined checksum. 78 79Limitations 80----------- 81 82* Scatter-Gather, SHA and Stateful are not supported. 83* Non-compressed block is not supported in compress (supported in decompress). 84 85Supported NICs 86-------------- 87 88* Mellanox\ |reg| BlueField 2 SmartNIC 89 90Prerequisites 91------------- 92 93- Mellanox OFED version: **5.2** 94 see :doc:`../../nics/mlx5` guide for more Mellanox OFED details. 95