[PATCH v4 3/4] doc: add topology grouping details

[Vipin Varghese]

Add `Topology` section into eal_init documentation.

Signed-off-by: Vipin Varghese <vipin.varghese at amd.com>
---
 .../prog_guide/env_abstraction_layer.rst      | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
index b9fac1839d..3ff6a17501 100644
--- a/doc/guides/prog_guide/env_abstraction_layer.rst
+++ b/doc/guides/prog_guide/env_abstraction_layer.rst
@@ -1188,3 +1188,25 @@ will not be deallocated.
 
 Any successful deallocation event will trigger a callback, for which user
 applications and other DPDK subsystems can register.
+
+Topology
+--------
+
+During `rte_eal_init`, an internal topology structure is created to group DPDK enabled
+lcores into various topology. Using HWLOC library, lcores are categorized into multiple
+domains based on topology groups such as
+
+*   L1 cache
+*   L2 cache
+*   L3 cache
+*   L4 cache
+*   IO
+
+Using `rte_lcore_` extended API, user can retrieve lcores from groups using topology flag and
+domain index. Refer to the API documentation for details.
+
+.. note::
+
+    Topology API are tested on HWLOC library version `2.7.0`.
+    In absence of HWLOC library, initialization of topology objects is skipped.
+    For cross compile, please ensure appropriate path for `pkg-config` is enabled.
-- 
2.34.1