--- /dev/null
+.. SPDX-License-Identifier: BSD-3-Clause
+ Copyright(c) 2018 Intel Corporation.
+
+ISA-L Compression Poll Mode Driver
+==================================
+
+The ISA-L PMD (**librte_pmd_isal_comp**) provides poll mode compression &
+decompression driver support for utilizing Intel ISA-L library,
+which implements the deflate algorithm for both Deflate(compression) and Inflate(decompression).
+
+
+Features
+--------
+
+ISA-L PMD has support for:
+
+Compression/Decompression algorithm:
+
+ * DEFLATE
+
+Huffman code type:
+
+ * FIXED
+ * DYNAMIC
+
+Window size support:
+
+ * 32K
+
+Level guide:
+
+The ISA-L levels have been mapped to somewhat correspond to the same ZLIB level,
+i.e. ZLIB L1 gives a compression ratio similar to ISA-L L1.
+Compressdev level 0 enables "No Compression", which passes the uncompressed
+data to the output buffer, plus deflate headers.
+The ISA-L library does not support this, therefore compressdev level 0 is not supported.
+
+The compressdev API has 10 levels, 0-9. ISA-L has 4 levels of compression, 0-3.
+As a result the level mappings from the API to the PMD are shown below.
+
+.. _table_ISA-L_compression_levels:
+
+.. table:: Level mapping from Compressdev to ISA-L PMD.
+
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | Compressdev | PMD Functionality | Internal ISA-L |
+ | API Level | | Level |
+ +=============+==============================================+===============================================+
+ | 0 | No compression, Not Supported | --- |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 1 | Dynamic (Fast compression) | 1 |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 2 | Dynamic | 2 |
+ | | (Higher compression ratio) | |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 3 | Dynamic | 3 |
+ | | (Best compression ratio) | (Level 2 if |
+ | | | no AVX512/AVX2) |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 4 | Dynamic (Best compression ratio) | Same as above |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 5 | Dynamic (Best compression ratio) | Same as above |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 6 | Dynamic (Best compression ratio) | Same as above |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 7 | Dynamic (Best compression ratio) | Same as above |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 8 | Dynamic (Best compression ratio) | Same as above |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+ | 9 | Dynamic (Best compression ratio) | Same as above |
+ +-------------+----------------------------------------------+-----------------------------------------------+
+
+.. Note::
+
+ The above table only shows mapping when API calls for dynamic compression.
+ For fixed compression, regardless of API level, internally ISA-L level 0 is always used.
+
+Limitations
+-----------
+
+* 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.
+
+* Compressdev level 0, no compression, is not supported.
+
+* Checksums will not be supported until future release.
+
+Installation
+------------
+
+* To build DPDK with Intel's ISA-L library, the user is required to download the library from `<https://github.com/01org/isa-l>`_.
+
+* Once downloaded, the user needs to build the library, the ISA-L autotools are usually sufficient::
+
+ ./autogen.sh
+ ./configure
+
+* make can be used to install the library on their system, before building DPDK::
+
+ make
+ sudo make install
+
+* To build with meson, the **libisal.pc** file, must be copied into "pkgconfig",
+ e.g. /usr/lib/pkgconfig or /usr/lib64/pkgconfig depending on your system,
+ for meson to find the ISA-L library. The **libisal.pc** is located in library sources::
+
+ cp isal/libisal.pc /usr/lib/pkgconfig/
+
+
+Initialization
+--------------
+
+In order to enable this virtual compression PMD, user must:
+
+* Set ``CONFIG_RTE_LIBRTE_PMD_ISAL=y`` in config/common_base.
+
+To use the PMD in an application, user must:
+
+* Call ``rte_vdev_init("compress_isal")`` within the application.
+
+* Use ``--vdev="compress_isal"`` in the EAL options, which will call ``rte_vdev_init()`` internally.
+
+The following parameter (optional) can be provided in the previous two calls:
+
+* ``socket_id:`` Specify the socket where the memory for the device is going to be allocated
+ (by default, socket_id will be the socket where the core that is creating the PMD is running on).
Code Review / deb_dpdk.git / blobdiff