[tor-commits] [tor/master] doc: Initial documentation of the lib/metrics

[ahf at torproject.org]

commit 1c06c9f1c0a496132a586ab8ff6ecf371b6ecf43
Author: David Goulet <dgoulet at torproject.org>
Date:   Thu Oct 22 15:11:58 2020 -0400

    doc: Initial documentation of the lib/metrics
    
    Signed-off-by: David Goulet <dgoulet at torproject.org>
---
 src/lib/metrics/lib_metrics.md | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/lib/metrics/lib_metrics.md b/src/lib/metrics/lib_metrics.md
new file mode 100644
index 0000000000..e58680e237
--- /dev/null
+++ b/src/lib/metrics/lib_metrics.md
@@ -0,0 +1,12 @@
+ at dir /lib/metrics
+ at brief lib/metrics: Metrics collection API
+
+This module is used for adding "metrics" support to Tor.
+
+Metrics are a collection of counters that are defined per-subsystem and
+accessed through the MetricsPort. Each subsystem is responsible for populating
+metrics store(s) and providing access to them through the `.get_metrics()`
+call located in the `subsys_fns_t` object.
+
+These metrics are meant to be extremely lightweight and thus can be accessed
+without too much CPU cost.