[Instrumentation.Process] Remove process.cpu.count

Remove the `process.cpu.count` metric which is not part of the Semantic Conventions.

Author: martincostello

src/OpenTelemetry.Instrumentation.Process/CHANGELOG.md

@@ -5,6 +5,12 @@
 * Add instrumentation scope version and schema URL to metrics.
   ([#4088](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4088))
 
+* Removed the `process.cpu.count` metric as it is not part of
+  the semantic conventions. Use the
+  [`dotnet.process.cpu.count`](https://github.com/open-telemetry/semantic-conventions/blob/v1.41.0/docs/runtime/dotnet-metrics.md#metric-dotnetprocesscpucount)
+  metric as an alternative.
+  ([#4088](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4088))
+
 ## 1.15.1-beta.1
 
 Released 2026-Apr-21

src/OpenTelemetry.Instrumentation.Process/ProcessMetrics.cs

@@ -47,15 +47,6 @@ static ProcessMetrics()
             unit: "s",
             description: "Total CPU seconds broken down by different states.");
 
-        MeterInstance.CreateObservableUpDownCounter(
-            "process.cpu.count",
-            () =>
-            {
-                return Environment.ProcessorCount;
-            },
-            unit: "{processors}",
-            description: "The number of processors (CPU cores) available to the current process.");
-
         MeterInstance.CreateObservableUpDownCounter(
             "process.thread.count",
             () =>

src/OpenTelemetry.Instrumentation.Process/README.md

@@ -118,24 +118,6 @@ Gets the user processor time for this process.
 * [Process.PrivilegedProcessorTime](https://learn.microsoft.com/dotnet/api/system.diagnostics.process.privilegedprocessortime):
 Gets the privileged processor time for this process.
 
-### process.cpu.count
-
-The number of processors (CPU cores) available to the current process.
-
-| Units         | Instrument Type         | Value Type |
-| ------------- | ----------------------- | ---------- |
-| `{processors}`| ObservableUpDownCounter | `Int32`    |
-
-The API used to retrieve the value is
-[System.Environment.ProcessorCount](https://learn.microsoft.com/dotnet/api/system.environment.processorcount).
-
-> [!NOTE]
-> This metric is under
-> [discussion](https://github.com/open-telemetry/opentelemetry-specification/issues/3200)
-and not part of the [Process Metrics
-Spec](https://github.com/open-telemetry/semantic-conventions/blob/main/docs/system/process-metrics.md)
-at this time.
-
 ### process.thread.count
 
 Process threads count.

test/OpenTelemetry.Instrumentation.Process.Tests/ProcessMetricsTests.cs

@@ -21,17 +21,15 @@ public void ProcessMetricsAreCaptured()
 
         meterProviderA.ForceFlush(MaxTimeToAllowForFlush);
 
-        Assert.Equal(5, exportedItemsA.Count);
         var physicalMemoryMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.memory.usage");
         Assert.NotNull(physicalMemoryMetric);
         var virtualMemoryMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.memory.virtual");
         Assert.NotNull(virtualMemoryMetric);
         var cpuTimeMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.cpu.time");
         Assert.NotNull(cpuTimeMetric);
-        var processorCountMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.cpu.count");
-        Assert.NotNull(processorCountMetric);
         var threadMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.thread.count");
         Assert.NotNull(threadMetric);
+        Assert.Equal(4, exportedItemsA.Count);
 
         exportedItemsA.Clear();
 
@@ -51,8 +49,8 @@ public void ProcessMetricsAreCaptured()
 
         meterProviderB.ForceFlush(MaxTimeToAllowForFlush);
 
-        Assert.Equal(5, exportedItemsA.Count);
-        Assert.Equal(5, exportedItemsB.Count);
+        Assert.Equal(4, exportedItemsA.Count);
+        Assert.Equal(4, exportedItemsB.Count);
 
         AssertMetrics(exportedItemsA);
         AssertMetrics(exportedItemsB);
@@ -132,29 +130,25 @@ public async Task ProcessMetricsAreCapturedWhenTasksOverlap()
 
         await Task.WhenAll(tasks);
 
-        Assert.Equal(5, exportedItemsA.Count);
         var physicalMemoryMetricA = exportedItemsA.FirstOrDefault(i => i.Name == "process.memory.usage");
         Assert.NotNull(physicalMemoryMetricA);
         var virtualMemoryMetricA = exportedItemsA.FirstOrDefault(i => i.Name == "process.memory.virtual");
         Assert.NotNull(virtualMemoryMetricA);
         var cpuTimeMetricA = exportedItemsA.FirstOrDefault(i => i.Name == "process.cpu.time");
         Assert.NotNull(cpuTimeMetricA);
-        var processorCountMetricA = exportedItemsA.FirstOrDefault(i => i.Name == "process.cpu.count");
-        Assert.NotNull(processorCountMetricA);
         var threadMetricA = exportedItemsA.FirstOrDefault(i => i.Name == "process.thread.count");
         Assert.NotNull(threadMetricA);
+        Assert.Equal(4, exportedItemsA.Count);
 
-        Assert.Equal(5, exportedItemsB.Count);
         var physicalMemoryMetricB = exportedItemsB.FirstOrDefault(i => i.Name == "process.memory.usage");
         Assert.NotNull(physicalMemoryMetricB);
         var virtualMemoryMetricB = exportedItemsB.FirstOrDefault(i => i.Name == "process.memory.virtual");
         Assert.NotNull(virtualMemoryMetricB);
         var cpuTimeMetricB = exportedItemsB.FirstOrDefault(i => i.Name == "process.cpu.time");
         Assert.NotNull(cpuTimeMetricB);
-        var processorCountMetricB = exportedItemsB.FirstOrDefault(i => i.Name == "process.cpu.count");
-        Assert.NotNull(processorCountMetricB);
         var threadMetricB = exportedItemsB.FirstOrDefault(i => i.Name == "process.thread.count");
         Assert.NotNull(threadMetricB);
+        Assert.Equal(4, exportedItemsB.Count);
 
         AssertMetrics(exportedItemsA);
         AssertMetrics(exportedItemsB);