Prom compatibility: allow disabling the addition of _total suffixes on prometheus counters (#3590)

Author: dashpole

CHANGELOG.md

@@ -19,6 +19,9 @@ release.
 
 ### Compatibility
 
+- Prometheus exporters SHOULD provide configuration to disable the addition of `_total` suffixes.
+  ([#3590](https://github.com/open-telemetry/opentelemetry-specification/pull/3590))
+
 ### SDK Configuration
 
 ### Common

specification/compatibility/prometheus_and_openmetrics.md

@@ -283,7 +283,7 @@ An [OpenTelemetry Gauge](../metrics/data-model.md#gauge) MUST be converted to a
   - The new data point's start time must match the time of the accumulated data point. If not, see [detecting alignment issues](../metrics/data-model.md#sums-detecting-alignment-issues).
 - Otherwise, it MUST be dropped.
 
-If the metric name for monotonic Sum metric points does not end in a suffix of `_total` a suffix of `_total` MUST be added, otherwise the name MUST remain unchanged.
+If the metric name for monotonic Sum metric points does not end in a suffix of `_total` a suffix of `_total` MUST be added by default, otherwise the name MUST remain unchanged. Exporters SHOULD provide a configuration option to disable the addition of `_total` suffixes.
 Monotonic Sum metric points with `StartTimeUnixNano` should export the `{name}_created` metric as well.
 
 ### Histograms