Metrics for System.Runtime

[JamesNK]

Today there are event counters for System.Runtime: https://learn.microsoft.com/en-us/dotnet/core/diagnostics/available-counters#systemruntime-counters

Metrics should be added to this area. Advantages:

1. Metrics has new features such as tags (allows for dimensions) and histograms.
2. Easier for tests and libraries to listen to and consume with MeterListener.
3. Some libraries only support collecting custom counters that use System.Diaganostics.Metrics. For example, opentelemetry-net.

What instruments should we have?

• Existing System.Runtime event counters provide a good starting place.
  • Some of these counters could be combined by using tags.
  • Or tags could provide more information. For example, should the exception-count counter include the exception type name as a tag? Then tooling can provide a breakdown of not just the total exception count but the exception count grouped by type.
• OpenTelemetry has specs with conventions for counters that a system provides. We should try to provide the same data. Note that counter and tag names don't need to match. We should use .NET conventions.
  • Process metrics
  • System metrics
  • Hardware metrics

[JamesNK]

cc @DamianEdwards @samsp-msft @noahfalk @tarekgh

[tarekgh]

CC @reyang

[reyang]

@JamesNK FYI in OpenTelemetry .NET we've implemented these:

• https://github.com/open-telemetry/opentelemetry-dotnet-contrib/tree/main/src/OpenTelemetry.Instrumentation.Runtime
• https://github.com/open-telemetry/opentelemetry-dotnet-contrib/tree/main/src/OpenTelemetry.Instrumentation.Process

Having these in in future versions of the runtime would be awesome, the existing OpenTelemetry instrumentation libraries can do a runtime detection and leverage the runtime instrumentation if it is there. Eventually as old versions of the runtime get deprecated, we'll land in a better situation where we don't need a separate instrumentation library as things are "baked in".

[JamesNK]

I think OTel would still have something because .NET counters won't follow the OTel naming standard. However, the implementation should be very simple because built-in counters will provide all the information needed.

[noahfalk]

@JamesNK is this work you were planning to pursue yourself or just recording the request?

[JamesNK]

Recording the request.