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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_compress_isal**) 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 30Checksum: 31 32 * CRC32 33 * ADLER32 34 35To enable a checksum in the driver, the compression and/or decompression xform 36structure, rte_comp_xform, must be filled with either of the CompressDev 37checksum flags supported. :: 38 39 compress_xform->compress.chksum = RTE_COMP_CHECKSUM_CRC32 40 41 decompress_xform->decompress.chksum = RTE_COMP_CHECKSUM_CRC32 42 43:: 44 45 compress_xform->compress.chksum = RTE_COMP_CHECKSUM_ADLER32 46 47 decompress_xform->decompress.chksum = RTE_COMP_CHECKSUM_ADLER32 48 49If you request a checksum for compression or decompression, 50the checksum field in the operation structure, ``op->output_chksum``, 51will be filled with the checksum. 52 53.. Note:: 54 55 For the compression case above, your output buffer will need to be large enough to hold the compressed data plus a scratchpad for the checksum at the end, the scratchpad is 8 bytes for CRC32 and 4 bytes for Adler32. 56 57Level guide: 58 59The ISA-L levels have been mapped to somewhat correspond to the same ZLIB level, 60i.e. ZLIB L1 gives a compression ratio similar to ISA-L L1. 61Compressdev level 0 enables "No Compression", which passes the uncompressed 62data to the output buffer, plus deflate headers. 63The ISA-L library does not support this, therefore compressdev level 0 is not supported. 64 65The compressdev API has 10 levels, 0-9. ISA-L has 4 levels of compression, 0-3. 66As a result the level mappings from the API to the PMD are shown below. 67 68.. _table_ISA-L_compression_levels: 69 70.. table:: Level mapping from Compressdev to ISA-L PMD. 71 72 +-------------+----------------------------------------------+-----------------------------------------------+ 73 | Compressdev | PMD Functionality | Internal ISA-L | 74 | API Level | | Level | 75 +=============+==============================================+===============================================+ 76 | 0 | No compression, Not Supported | --- | 77 +-------------+----------------------------------------------+-----------------------------------------------+ 78 | 1 | Dynamic (Fast compression) | 1 | 79 +-------------+----------------------------------------------+-----------------------------------------------+ 80 | 2 | Dynamic | 2 | 81 | | (Higher compression ratio) | | 82 +-------------+----------------------------------------------+-----------------------------------------------+ 83 | 3 | Dynamic | 3 | 84 | | (Best compression ratio) | (Level 2 if | 85 | | | no AVX512/AVX2) | 86 +-------------+----------------------------------------------+-----------------------------------------------+ 87 | 4 | Dynamic (Best compression ratio) | Same as above | 88 +-------------+----------------------------------------------+-----------------------------------------------+ 89 | 5 | Dynamic (Best compression ratio) | Same as above | 90 +-------------+----------------------------------------------+-----------------------------------------------+ 91 | 6 | Dynamic (Best compression ratio) | Same as above | 92 +-------------+----------------------------------------------+-----------------------------------------------+ 93 | 7 | Dynamic (Best compression ratio) | Same as above | 94 +-------------+----------------------------------------------+-----------------------------------------------+ 95 | 8 | Dynamic (Best compression ratio) | Same as above | 96 +-------------+----------------------------------------------+-----------------------------------------------+ 97 | 9 | Dynamic (Best compression ratio) | Same as above | 98 +-------------+----------------------------------------------+-----------------------------------------------+ 99 100.. Note:: 101 102 The above table only shows mapping when API calls for dynamic compression. 103 For fixed compression, regardless of API level, internally ISA-L level 0 is always used. 104 105 106Limitations 107----------- 108 109* Compressdev level 0, no compression, is not supported. 110 111Installation 112------------ 113 114* To build DPDK with Intel's ISA-L library, the user is required to download the library from `<https://github.com/01org/isa-l>`_. 115 116* Once downloaded, the user needs to build the library, the ISA-L autotools are usually sufficient:: 117 118 ./autogen.sh 119 ./configure 120 121* make can be used to install the library on their system, before building DPDK:: 122 123 make 124 sudo make install 125 126* To build with meson, the **libisal.pc** file, must be copied into "pkgconfig", 127 e.g. /usr/lib/pkgconfig or /usr/lib64/pkgconfig depending on your system, 128 for meson to find the ISA-L library. The **libisal.pc** is located in library sources:: 129 130 cp isal/libisal.pc /usr/lib/pkgconfig/ 131 132 133Initialization 134-------------- 135 136To use the PMD in an application, user must: 137 138* Call ``rte_vdev_init("compress_isal")`` within the application. 139 140* Use ``--vdev="compress_isal"`` in the EAL options, which will call ``rte_vdev_init()`` internally. 141 142The following parameter (optional) can be provided in the previous two calls: 143 144* ``socket_id:`` Specify the socket where the memory for the device is going to be allocated 145 (by default, socket_id will be the socket where the core that is creating the PMD is running on). 146