How do you monitor live performance metrics and memory usage in .NET with System.Diagnostics.Metrics and OpenTelemetry?

Short answer

Use Meter and Counter to record business and performance metrics, then export them in the standard Prometheus format for Grafana dashboards.

Explanation

Modern .NET unifies metrics under System.Diagnostics.Metrics, which is compatible with OpenTelemetry. Instead of relying on old Windows-only Performance Counters, Meter provides lightweight, standard Counters, Histograms, and UpDownCounters that work on Linux and Windows and can be exported to distributed monitoring systems through a /metrics endpoint.

Code example

private static readonly Meter MyMeter = new("MyApp.Orders");
private static readonly Counter<int> OrdersPlaced = MyMeter.CreateCounter<int>("orders_total");

public void PlaceOrder() {
    OrdersPlaced.Add(1, new KeyValuePair<string, object?>("country", "EG"));
}

Common mistakes

• Creating new Meter objects for every request instead of defining one as static or sharing it as a Singleton.

Follow-up questions

• Why is GeneratedRegex in .NET 7+ better than creating new Regex() objects at runtime?

Sources

• Microsoft Learn — System.Diagnostics.Metrics overview