+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
+-----------