doc: fix RSS flow description in i40e guide

[dpdk.git] / doc / guides / compressdevs / isal.rst

diff --git a/doc/guides/compressdevs/isal.rst b/doc/guides/compressdevs/isal.rst
index 276ff06..029f8e2 100644 (file)
--- a/doc/guides/compressdevs/isal.rst
+++ b/doc/guides/compressdevs/isal.rst
@@ -4,7 +4,7 @@
 ISA-L Compression Poll Mode Driver
 ==================================
 
-The ISA-L PMD (**librte_pmd_isal_comp**) provides poll mode compression &
+The ISA-L PMD (**librte_compress_isal**) 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).
 
@@ -27,6 +27,33 @@ Window size support:
 
     * 32K
 
+Checksum:
+
+    * CRC32
+    * ADLER32
+
+To enable a checksum in the driver, the compression and/or decompression xform
+structure, rte_comp_xform, must be filled with either of the CompressDev
+checksum flags supported. ::
+
+ compress_xform->compress.chksum = RTE_COMP_CHECKSUM_CRC32
+
+ decompress_xform->decompress.chksum = RTE_COMP_CHECKSUM_CRC32
+
+::
+
+ compress_xform->compress.chksum = RTE_COMP_CHECKSUM_ADLER32
+
+ decompress_xform->decompress.chksum = RTE_COMP_CHECKSUM_ADLER32
+
+If you request a checksum for compression or decompression,
+the checksum field in the operation structure,  ``op->output_chksum``,
+will be filled with the checksum.
+
+.. Note::
+
+ 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.
+
 Level guide:
 
 The ISA-L levels have been mapped to somewhat correspond to the same ZLIB level,
@@ -75,15 +102,12 @@ As a result the level mappings from the API to the PMD are shown below.
  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
 ------------
 
@@ -109,10 +133,6 @@ Installation
 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.