There is a number of dotnet CLI tools like:

• dotnet-counters

  a performance monitoring tool for ad-hoc health monitoring and first-level performance investigation. It can observe performance counter values that are published via the EventCounter API or the Meter API. For example, you can quickly monitor things like the CPU usage or the rate of exceptions being thrown in your .NET Core application to see if there's anything suspicious before diving into more serious performance investigation using PerfView or dotnet-trace.

• dotnet-monitor

  global tool is a way to monitor .NET applications in production environments and to collect diagnostic artefacts (for example, dumps, traces, logs, and metrics) on-demand or using automated rules for collecting under specified conditions.

They do not require installing Visual Studio on the machine (though they require SDK being installed).

Metric collection is a vast and quite complicated topic. There quite a lot of tools making life easier, for example prometheus-net or OpenTelemetry which allows metric collection including distributed environments.

Another possibility is to "manually" integrate this collection into the app via corresponding APIs or using other performance diagnostic tools

Diagnose and solve performance problems in net-core

Unlike the .NET Framework on Windows, .NET Core doesn’t emit perf counters. Instead, we had introduced a new way of emitting metrics in .NET Core via the EventCounter API.

EventCounters offer an improvement over Windows perf counters as these are now usable on all OSes where .NET Core is supported.

EventCounters

EventCounters are .NET APIs used for lightweight, cross-platform, and near real-time performance metric collection. EventCounters were added as a cross-platform alternative to the "performance counters" of .NET Framework on Windows.

You can use these performance diagnostic tools designed for .NET Core :

• dotnet-trace

• dotnet-counters

Example Usage of dotnet-counters:

1. Install the tool

   dotnet tool install --global dotnet-counters

2. Run command below to make dotnet-counters create a diagnostics socket named myport.sock and wait for a connection.

   dotnet-counters collect --diagnostic-port myport.sock

3. Set DOTNET_DiagnosticPorts=myport.sock in your application's environment variables which will enable dotnet-counters to start collecting counters on your app and run your app.

Output of the command in 2:

By default dotnet-counters will collect/monitor the Well-known EventCounters, The counters I believe you are specifically interested in are the System.Runtime counters i.e Monitor Lock Contention Count,ThreadPool Queue Length and ThreadPool Thread Count (These are monitored/collected by default).