bufmon: add buffer monitoring plugin

This plugin allow to keep track of buffer usage in VPP graph nodes. The
main use is to detect buffer leakages.

Type: feature

Change-Id: Iadcf4ab98207fab6e2fa375060879bc2a25b711e
Signed-off-by: Benoît Ganne <bganne@cisco.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/src/plugins/bufmon/bufmon_doc.md b/src/plugins/bufmon/bufmon_doc.md
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+# Buffers monitoring plugin {#bufmon_doc}
+
+This plugin enables to track buffer utilization in the VPP graph nodes. The
+main use is to detect buffer leakage.
+It works by keeping track of number of buffer allocations and free in graph
+nodes and also of number of buffers received in input frames and in output
+frames.
+The formula to compute the number of "buffered" buffers in a node is simply:
+        #buffered = #alloc + #input - #free - #output
+Note: monitoring will impact performances.
+
+## Basic usage
+1. Turn buffer traces on:
+```
+~# vppctl set buffer traces on
+```
+2. Monitor buffer usage:
+```
+~# vppctl show buffer traces verbose
+```
+3. Turn buffer traces off:
+```
+~# vppctl set buffer traces off
+```