[Instrumentation.Process] Exposed required metric process.cpu.count for computing CPU utilization in the backend.

src/OpenTelemetry.Instrumentation.Process/CHANGELOG.md

@@ -2,7 +2,8 @@
 
 ## Unreleased
 
-TBD
+* Added `process.cpu.count` metric.
+  ([#981](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/981))
 
 ## 1.0.0-alpha.6
 

src/OpenTelemetry.Instrumentation.Process/ProcessMetrics.cs

@@ -16,6 +16,7 @@
 
 #nullable enable
 
+using System;
 using System.Collections.Generic;
 using System.Diagnostics.Metrics;
 using System.Reflection;
@@ -64,6 +65,15 @@ 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.threads",
             () =>

src/OpenTelemetry.Instrumentation.Process/README.md

@@ -92,6 +92,23 @@ 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][1] and not part of the
+[Process Metrics Spec][2] at this time.
+
+[1]: https://github.com/open-telemetry/opentelemetry-specification/issues/3200
+[2]: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/process-metrics.md
+
 ### process.threads
 
 Process threads count.

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

@@ -38,14 +38,16 @@ public void ProcessMetricsAreCaptured()
 
         meterProviderA.ForceFlush(MaxTimeToAllowForFlush);
 
-        Assert.True(exportedItemsA.Count == 4);
+        Assert.True(exportedItemsA.Count == 5);
         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 threadMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.threads");
+        var processorCountMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.cpu.count");
+        Assert.NotNull(processorCountMetric);
+        var threadMetric = exportedItemsA.FirstOrDefault(i => i.Name == "process.cpu.count");
         Assert.NotNull(threadMetric);
 
         exportedItemsA.Clear();
@@ -66,8 +68,8 @@ public void ProcessMetricsAreCaptured()
 
         meterProviderB.ForceFlush(MaxTimeToAllowForFlush);
 
-        Assert.True(exportedItemsA.Count == 4);
-        Assert.True(exportedItemsB.Count == 4);
+        Assert.True(exportedItemsA.Count == 5);
+        Assert.True(exportedItemsB.Count == 5);
     }
 
     [Fact]
@@ -142,23 +144,27 @@ public void ProcessMetricsAreCapturedWhenTasksOverlap()
 
         Task.WaitAll(tasks.ToArray());
 
-        Assert.True(exportedItemsA.Count == 4);
+        Assert.True(exportedItemsA.Count == 5);
         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.threads");
         Assert.NotNull(threadMetricA);
 
-        Assert.True(exportedItemsB.Count == 4);
+        Assert.True(exportedItemsB.Count == 5);
         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.threads");
         Assert.NotNull(threadMetricB);
     }