[4/5] doc: add mlx5 design details
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Commit Message
Some details about libibverbs were missing:
- automatic detection by meson
- main ways to access the device
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---
doc/guides/nics/mlx5.rst | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
@@ -20,12 +20,12 @@ There is also a `section dedicated to this poll mode driver
.. note::
- Due to external dependencies, this driver is disabled by default. It must
- be enabled manually by setting ``CONFIG_RTE_LIBRTE_MLX5_PMD=y`` and
- recompiling DPDK.
+ Due to external dependencies, this driver is disabled in default configuration
+ of the "make" build. It can be enabled with ``CONFIG_RTE_LIBRTE_MLX5_PMD=y``
+ or by using "meson" build system which will detect dependencies.
-Implementation details
-----------------------
+Design
+------
Besides its dependency on libibverbs (that implies libmlx5 and associated
kernel support), librte_pmd_mlx5 relies heavily on system calls for control
@@ -44,6 +44,16 @@ This means legacy linux control tools (for example: ethtool, ifconfig and
more) can operate on the same network interfaces that owned by the DPDK
application.
+The PMD can use libibverbs and libmlx5 to access the device firmware
+or directly the hardware components.
+There are different levels of objects and bypassing abilities
+to get the best performances:
+
+- Verbs is a complete high-level generic API
+- Direct Verbs is a device-specific API
+- DevX allows to access firmware objects
+- Direct Rules manages flow steering at low-level hardware layer
+
Enabling librte_pmd_mlx5 causes DPDK applications to be linked against
libibverbs.