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SPDX-License-Identifier: BSD-3-Clause 2 Copyright(c) 2018 Intel Corporation. 3 4ISA-L Compression Poll Mode Driver 5================================== 6 7The ISA-L PMD (**librte_pmd_isal_comp**) provides poll mode compression & 8decompression driver support for utilizing Intel ISA-L library, 9which implements the deflate algorithm for both Deflate(compression) and Inflate(decompression). 10 11 12Features 13-------- 14 15ISA-L PMD has support for: 16 17Compression/Decompression algorithm: 18 19 * DEFLATE 20 21Huffman code type: 22 23 * FIXED 24 * DYNAMIC 25 26Window size support: 27 28 * 32K 29 30Level guide: 31 32The ISA-L levels have been mapped to somewhat correspond to the same ZLIB level, 33i.e. ZLIB L1 gives a compression ratio similar to ISA-L L1. 34Compressdev level 0 enables "No Compression", which passes the uncompressed 35data to the output buffer, plus deflate headers. 36The ISA-L library does not support this, therefore compressdev level 0 is not supported. 37 38The compressdev API has 10 levels, 0-9. ISA-L has 4 levels of compression, 0-3. 39As a result the level mappings from the API to the PMD are shown below. 40 41.. _table_ISA-L_compression_levels: 42 43.. table:: Level mapping from Compressdev to ISA-L PMD. 44 45 +-------------+----------------------------------------------+-----------------------------------------------+ 46 | Compressdev | PMD Functionality | Internal ISA-L | 47 | API Level | | Level | 48 +=============+==============================================+===============================================+ 49 | 0 | No compression, Not Supported | --- | 50 +-------------+----------------------------------------------+-----------------------------------------------+ 51 | 1 | Dynamic (Fast compression) | 1 | 52 +-------------+----------------------------------------------+-----------------------------------------------+ 53 | 2 | Dynamic | 2 | 54 | | (Higher compression ratio) | | 55 +-------------+----------------------------------------------+-----------------------------------------------+ 56 | 3 | Dynamic | 3 | 57 | | (Best compression ratio) | (Level 2 if | 58 | | | no AVX512/AVX2) | 59 +-------------+----------------------------------------------+-----------------------------------------------+ 60 | 4 | Dynamic (Best compression ratio) | Same as above | 61 +-------------+----------------------------------------------+-----------------------------------------------+ 62 | 5 | Dynamic (Best compression ratio) | Same as above | 63 +-------------+----------------------------------------------+-----------------------------------------------+ 64 | 6 | Dynamic (Best compression ratio) | Same as above | 65 +-------------+----------------------------------------------+-----------------------------------------------+ 66 | 7 | Dynamic (Best compression ratio) | Same as above | 67 +-------------+----------------------------------------------+-----------------------------------------------+ 68 | 8 | Dynamic (Best compression ratio) | Same as above | 69 +-------------+----------------------------------------------+-----------------------------------------------+ 70 | 9 | Dynamic (Best compression ratio) | Same as above | 71 +-------------+----------------------------------------------+-----------------------------------------------+ 72 73.. Note:: 74 75 The above table only shows mapping when API calls for dynamic compression. 76 For fixed compression, regardless of API level, internally ISA-L level 0 is always used. 77 78Limitations 79----------- 80 81* Chained mbufs will not be supported until a future release, meaning max data size being passed to PMD through a single mbuf is 64K - 1. If data is larger than this it will need to be split up and sent as multiple operations. 82 83* Compressdev level 0, no compression, is not supported. 84 85* Checksums will not be supported until future release. 86 87Installation 88------------ 89 90* To build DPDK with Intel's ISA-L library, the user is required to download the library from `<https://github.com/01org/isa-l>`_. 91 92* Once downloaded, the user needs to build the library, the ISA-L autotools are usually sufficient:: 93 94 ./autogen.sh 95 ./configure 96 97* make can be used to install the library on their system, before building DPDK:: 98 99 make 100 sudo make install 101 102* To build with meson, the **libisal.pc** file, must be copied into "pkgconfig", 103 e.g. /usr/lib/pkgconfig or /usr/lib64/pkgconfig depending on your system, 104 for meson to find the ISA-L library. The **libisal.pc** is located in library sources:: 105 106 cp isal/libisal.pc /usr/lib/pkgconfig/ 107 108 109Initialization 110-------------- 111 112In order to enable this virtual compression PMD, user must: 113 114* Set ``CONFIG_RTE_LIBRTE_PMD_ISAL=y`` in config/common_base. 115 116To use the PMD in an application, user must: 117 118* Call ``rte_vdev_init("compress_isal")`` within the application. 119 120* Use ``--vdev="compress_isal"`` in the EAL options, which will call ``rte_vdev_init()`` internally. 121 122The following parameter (optional) can be provided in the previous two calls: 123 124* ``socket_id:`` Specify the socket where the memory for the device is going to be allocated 125 (by default, socket_id will be the socket where the core that is creating the PMD is running on). 126