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Migrate from .NET Framework Windows Performance Counters to .NET metrics

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.NET Framework applications, which only run on Windows, can use Windows Performance Counters to monitor application health and performance. However, in .NET Core and later versions, the platform provides cross-platform alternatives through the EventCounters and System.Diagnostics.Metrics APIs.

This article provides guidance on migrating from Windows Performance Counters to the newer metrics systems available in modern .NET versions.

A short history of .NET metrics

.NET applications can be monitored using different mechanisms depending on the .NET version and platform:

  • .NET Framework: Primarily uses Windows Performance Counters (Windows only)
  • .NET Core 3.0-3.1, .NET 5+: Introduced EventCounters (cross-platform) and built-in runtime metrics, networking metrics, and ASP.NET metrics using these APIs
  • .NET 6+: Added System.Diagnostics.Metrics API (cross-platform, OpenTelemetry compatible)
  • .NET 8+: Added built-in networking metrics and ASP.NET metrics using the new System.Diagnostics.Metrics API
  • .NET 9+: Added built-in runtime metrics using the new System.Diagnostics.Metrics API

The newer metrics systems offer several advantages:

  • Cross-platform operation: Works on Windows, Linux, macOS
  • Container-friendly: Works in containerized environments
  • Modern tooling: Integrates with OpenTelemetry and observability platforms
  • Supports xcopy install: No additional installation steps or privileges are required

For more information, see the Metrics API comparison.

Collect metrics in modern .NET applications

To collect and analyze metrics, see the System.Diagnostics.Metrics and EventCounters guides.

Map common Windows Performance Counters to modern metrics

If the monitoring system for your .NET Framework application uses runtime-provided Windows Performance Counters, you'll need to select alternative EventCounters or System.Diagnostics.Metrics-based metrics instead. The following tables show alternatives for many common counters. Not all .NET Framework counters have been ported to new alternatives. In some cases, infrequently used counters were discontinued, and in other cases, implementation changes in the platform have made certain counters irrelevant.

Memory counters

Windows Performance Counter EventCounter equivalent Metrics API equivalent
.NET CLR Memory\# Bytes in all Heaps System.Runtime\GC Heap Size (gc-heap-size) System.Runtime\dotnet.gc.last_collection.heap.size
.NET CLR Memory\# Gen 0 Collections System.Runtime\Gen 0 GC Count (gen-0-gc-count) System.Runtime\dotnet.gc.collections with attribute gc.heap.generation=gen0
.NET CLR Memory\# Gen 1 Collections System.Runtime\Gen 1 GC Count (gen-1-gc-count) System.Runtime\dotnet.gc.collections with attribute gc.heap.generation=gen1
.NET CLR Memory\# Gen 2 Collections System.Runtime\Gen 2 GC Count (gen-2-gc-count) System.Runtime\dotnet.gc.collections with attribute gc.heap.generation=gen2
.NET CLR Memory\% Time in GC System.Runtime\% Time in GC since last GC (time-in-gc) System.Runtime\dotnet.gc.pause.time (calculate as percentage of total time)
.NET CLR Memory\# Total committed Bytes None System.Runtime\dotnet.gc.last_collection.memory.committed_size
.NET CLR Memory\Large Object Heap Size System.Runtime\LOH Size (loh-size) System.Runtime\dotnet.gc.last_collection.heap.size with attribute gc.heap.generation=loh
.NET CLR Memory\Allocated Bytes/sec System.Runtime\Allocation Rate (alloc-rate) Calculate rate from System.Runtime\dotnet.gc.heap.total_allocated

Note

dotnet.gc.pause.time allows an improved calculation that avoids some undesirable behavior in the older % Time in GC metric. % Time in GC computed 100 * pause_time_in_most_recent_GC / time_between_most_recent_two_GCs. In some cases two GCs would occur very close together producing a high value based on a tiny non-representative portion of the overall time interval. gc.heap.pause.time accumulates the total time the GC has paused application threads so far in a process, which allows computing the GC pause time during any measured time interval. This is a truer measurement of GC overhead, but the change in calculation means the metrics might not match even when the underlying GC behavior is unchanged.

JIT and Loading counters

Windows Performance Counter EventCounter equivalent Metrics API equivalent
.NET CLR Jit\# of Methods Jitted System.Runtime\Methods Jitted Count (methods-jitted-count) System.Runtime\dotnet.jit.compiled_methods
.NET CLR Jit\IL Bytes Jitted System.Runtime\IL Bytes Jitted (il-bytes-jitted) System.Runtime\dotnet.jit.compiled_il.size
.NET CLR Loading\Current Assemblies System.Runtime\Number of Assemblies Loaded (assembly-count) System.Runtime\dotnet.assembly.count
.NET CLR Jit\Total # of IL Bytes Jitted System.Runtime\IL Bytes Jitted (il-bytes-jitted) System.Runtime\dotnet.jit.compiled_il.size

Threading counters

Windows Performance Counter EventCounter equivalent Metrics API equivalent
.NET CLR LocksAndThreads\Current Queue Length System.Runtime\ThreadPool Queue Length (threadpool-queue-length) System.Runtime\dotnet.thread_pool.queue.length
.NET CLR LocksAndThreads\Contention Rate / sec System.Runtime\Monitor Lock Contention Count (monitor-lock-contention-count) Calculate rate from System.Runtime\dotnet.monitor.lock_contentions

Exceptions counters

Windows Performance Counter EventCounter equivalent Metrics API equivalent
.NET CLR Exceptions\# of Exceps Thrown / sec System.Runtime\Exception Count (exception-count) Calculate rate from System.Runtime\dotnet.exceptions
.NET CLR Exceptions\# of Exceps Thrown None System.Runtime\dotnet.exceptions

Socket networking counters

Windows Performance Counter EventCounter equivalent Metrics API equivalent
.NET CLR Networking\Bytes Received System.Net.Sockets\Bytes Received (bytes-received) None
.NET CLR Networking\Bytes Sent System.Net.Sockets\Bytes Sent (bytes-sent) None
.NET CLR Networking\Connections Established System.Net.Sockets\Outgoing Connections Established (outgoing-connections-established) None
.NET CLR Networking\Datagrams Received System.Net.Sockets\Datagrams Received (datagrams-received) None
.NET CLR Networking\Datagrams Sent System.Net.Sockets\Datagrams Sent (datagrams-sent) None

DNS networking counters

Windows Performance Counter EventCounter equivalent Metrics API equivalent
.NET CLR Networking\DNS Lookups System.Net.NameResolution\DNS Lookups Requested (dns-lookups-requested) Sum the histogram buckets in System.Net.NameResolution\dns.lookup.duration
.NET CLR Networking\DNS Resolution Time System.Net.NameResolution\Average DNS Lookup Duration (dns-lookups-duration) System.Net.NameResolution\dns.lookup.duration

HttpWebRequest counters

HttpWebRequest has been superseded by HttpClient. To learn what metrics are built-in, see the HttpClient EventCounters and System.Diagnostics.Metrics.

ASP.NET counters

ASP.NET has changed dramatically between .NET Framework and .NET Core. Many counters are obsolete or are measured differently than in the past. To learn what metrics are built-in, see the ASP.NET EventCounters and System.Diagnostics.Metrics.

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