feat: flip swap mechanism — MD as primary, RST as override (Phase 1)

This is the first of three phases inverting the per-page swap mechanism
so MD becomes the canonical primary and RST becomes the rare override.

Phase 1 — file renames + conf.py exclude_patterns flip only:
- Rename docs/**/md-<stem>.md to docs/**/<stem>.md (drop md- prefix)
  for all 254 stems previously listed in docs/_swap.txt
- Rename docs/**/<stem>.rst to docs/**/rst-<stem>.rst (add rst- prefix)
  for the same 254 stems
- Repurpose docs/_swap.txt as docs/_rst_overrides.txt; initially empty
  comment-only since no pages need the RST fallback right now
- conf.py exclude_patterns flipped: rst-*.rst is now excluded by default
  instead of md-*.md
- conf.py runtime-artifact references updated to _rst_override_state.json
  and _md_exclude.txt (Phase 2 will rewrite swap_sources.py to produce
  these names; for now no swap script runs because overrides list is empty)

Phase 2 (next commit on this branch) will rewrite scripts/swap_sources.py
with inverted rename direction, delete scripts/import_myst.py + tests, and
update tests/test_swap_sources.py for the new semantics.

Phase 3 will be the cleanup pass and ready-for-review flip.

Generated by robots https://vyos.io

1 files changed, 71 insertions, 0 deletions

diff --git a/docs/vpp/configuration/dataplane/cpu.md b/docs/vpp/configuration/dataplane/cpu.md
new file mode 100644
index 00000000..d92f6587
--- /dev/null
+++ b/docs/vpp/configuration/dataplane/cpu.md
@@ -0,0 +1,71 @@
+---
+lastproofread: '2026-02-23'
+---
+
+(vpp-config-dataplane-cpu)=
+
+```{include} /_include/need_improvement.txt
+```
+
+
+# VPP Dataplane CPU Configuration
+
+VPP can utilize multiple CPU cores for better packet processing
+performance. Proper CPU configuration is essential for optimal
+throughput and low latency.
+
+VPP CPU assignment is handled automatically. You specify how many CPU
+cores VPP may use, and the system distributes them between the main
+thread and worker threads.
+
+:::{important}
+Review the system configuration settings page before changing CPU
+settings: {doc}`system`.
+:::
+
+If you don't configure CPU settings, VPP uses a single core for the
+main thread and doesn't create worker threads.
+
+## CPU Configuration Parameters
+
+### `cpu-cores`
+
+This parameter defines the total number of CPU cores allocated to VPP.
+
+```{cfgcmd} set vpp settings resource-allocation cpu-cores \<core-number\>
+```
+
+The system automatically assigns cores using the following rules:
+
+> - The first two CPU cores are always reserved for the operating system and
+>   other services.
+> - The main VPP thread is assigned to the first available core after the
+>   reserved ones.
+> - The remaining allocated cores are used for worker threads.
+
+For example:
+
+> - If cpu-cores is set to 1, VPP runs only a main thread.
+>
+> - If cpu-cores is set to 4, VPP uses:
+>
+>   > - 1 core for the main thread
+>   > - 3 cores for worker threads
+
+Choose a value based on available hardware resources and expected
+traffic load. Too few cores may limit performance, while too many can
+negatively impact other system services.
+
+## Potential Issues and Troubleshooting
+
+Improper CPU configuration can lead to issues such as:
+
+- VPP underperformance when not enough cores are assigned, or kernel
+  underperformance when too many cores are assigned to VPP.
+- Resource conflicts with other processes and services.
+
+Indicators of such issues are:
+
+- VPP or kernel forwarding performance is lower than expected
+- Degraded performance of system components or services, such as DNS,
+  DHCP, and dynamic routing