Introducing Environment.CpuUsage

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Metrics/RuntimeMetrics.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
+using System.Runtime.Versioning;
 using System.Threading;
 
 namespace System.Diagnostics.Metrics
@@ -146,12 +147,14 @@ static RuntimeMetrics()
             unit: "{cpu}",
             description: "The number of processors available to the process.");
 
-        // TODO - Uncomment once an implementation for https://github.com/dotnet/runtime/issues/104844 is available.
-        //private static readonly ObservableCounter<double> s_processCpuTime = s_meter.CreateObservableCounter(
-        //    "dotnet.process.cpu.time",
-        //    GetCpuTime,
-        //    unit: "s",
-        //    description: "CPU time used by the process as reported by the CLR.");
+        private static readonly ObservableCounter<double>? s_processCpuTime =
+                                    OperatingSystem.IsBrowser() || OperatingSystem.IsTvOS() || (OperatingSystem.IsIOS() && !OperatingSystem.IsMacCatalyst()) ?
+                                    null :
+                                    s_meter.CreateObservableCounter(
+                                        "dotnet.process.cpu.time",
+                                        GetCpuTime,
+                                        unit: "s",
+                                        description: "CPU time used by the process.");
 
         public static bool IsEnabled()
         {
@@ -172,8 +175,8 @@ public static bool IsEnabled()
                 || s_threadPoolQueueLength.Enabled
                 || s_assembliesCount.Enabled
                 || s_exceptions.Enabled
-                || s_processCpuCount.Enabled;
-            //|| s_processCpuTime.Enabled;
+                || s_processCpuCount.Enabled
+                || s_processCpuTime?.Enabled is true;
         }
 
         private static IEnumerable<Measurement<long>> GetGarbageCollectionCounts()
@@ -188,17 +191,20 @@ private static IEnumerable<Measurement<long>> GetGarbageCollectionCounts()
             }
         }
 
-        // TODO - Uncomment once an implementation for https://github.com/dotnet/runtime/issues/104844 is available.
-        //private static IEnumerable<Measurement<double>> GetCpuTime()
-        //{
-        //    if (OperatingSystem.IsBrowser() || OperatingSystem.IsTvOS() || OperatingSystem.IsIOS())
-        //        yield break;
+        [SupportedOSPlatform("maccatalyst")]
+        [UnsupportedOSPlatform("ios")]
+        [UnsupportedOSPlatform("tvos")]
+        [UnsupportedOSPlatform("browser")]
+        private static IEnumerable<Measurement<double>> GetCpuTime()
+        {
+            Debug.Assert(s_processCpuTime is not null);
+            Debug.Assert(!OperatingSystem.IsBrowser() && !OperatingSystem.IsTvOS() && !(OperatingSystem.IsIOS() && !OperatingSystem.IsMacCatalyst()));
 
-        //    ProcessCpuUsage processCpuUsage = Environment.CpuUsage;
+            Environment.ProcessCpuUsage processCpuUsage = Environment.CpuUsage;
 
-        //    yield return new(processCpuUsage.UserTime.TotalSeconds, [new KeyValuePair<string, object?>("cpu.mode", "user")]);
-        //    yield return new(processCpuUsage.PrivilegedTime.TotalSeconds, [new KeyValuePair<string, object?>("cpu.mode", "system")]);
-        //}
+            yield return new(processCpuUsage.UserTime.TotalSeconds, [new KeyValuePair<string, object?>("cpu.mode", "user")]);
+            yield return new(processCpuUsage.PrivilegedTime.TotalSeconds, [new KeyValuePair<string, object?>("cpu.mode", "system")]);
+        }
 
         private static IEnumerable<Measurement<long>> GetHeapSizes()
         {

src/libraries/System.Diagnostics.DiagnosticSource/tests/RuntimeMetricsTests.cs

@@ -112,48 +112,47 @@ public void GcCollectionsCount()
             }
         }
 
-        // TODO - Uncomment once an implementation for https://github.com/dotnet/runtime/issues/104844 is available.
-        //[Fact]
-        //public void CpuTime()
-        //{
-        //    using InstrumentRecorder<double> instrumentRecorder = new("dotnet.process.cpu.time");
-
-        //    instrumentRecorder.RecordObservableInstruments();
-
-        //    bool[] foundCpuModes = [false, false];
-
-        //    foreach (Measurement<double> measurement in instrumentRecorder.GetMeasurements().Where(m => m.Value >= 0))
-        //    {
-        //        var tags = measurement.Tags.ToArray();
-        //        var tag = tags.SingleOrDefault(k => k.Key == "cpu.mode");
-
-        //        if (tag.Key is not null)
-        //        {
-        //            Assert.True(tag.Value is string, "Expected CPU mode tag to be a string.");
-
-        //            string tagValue = (string)tag.Value;
-
-        //            switch (tagValue)
-        //            {
-        //                case "user":
-        //                    foundCpuModes[0] = true;
-        //                    break;
-        //                case "system":
-        //                    foundCpuModes[1] = true;
-        //                    break;
-        //                default:
-        //                    Assert.Fail($"Unexpected CPU mode tag value '{tagValue}'.");
-        //                    break;
-        //            }
-        //        }
-        //    }
-
-        //    for (int i = 0; i < foundCpuModes.Length; i++)
-        //    {
-        //        var mode = i == 0 ? "user" : "system";
-        //        Assert.True(foundCpuModes[i], $"Expected to find a measurement for '{mode}' CPU mode.");
-        //    }
-        //}
+        [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotBrowser))]
+        public void CpuTime()
+        {
+           using InstrumentRecorder<double> instrumentRecorder = new("dotnet.process.cpu.time");
+
+           instrumentRecorder.RecordObservableInstruments();
+
+           bool[] foundCpuModes = [false, false];
+
+           foreach (Measurement<double> measurement in instrumentRecorder.GetMeasurements().Where(m => m.Value >= 0))
+           {
+               var tags = measurement.Tags.ToArray();
+               var tag = tags.SingleOrDefault(k => k.Key == "cpu.mode");
+
+               if (tag.Key is not null)
+               {
+                   Assert.True(tag.Value is string, "Expected CPU mode tag to be a string.");
+
+                   string tagValue = (string)tag.Value;
+
+                   switch (tagValue)
+                   {
+                       case "user":
+                           foundCpuModes[0] = true;
+                           break;
+                       case "system":
+                           foundCpuModes[1] = true;
+                           break;
+                       default:
+                           Assert.Fail($"Unexpected CPU mode tag value '{tagValue}'.");
+                           break;
+                   }
+               }
+           }
+
+           for (int i = 0; i < foundCpuModes.Length; i++)
+           {
+               var mode = i == 0 ? "user" : "system";
+               Assert.True(foundCpuModes[i], $"Expected to find a measurement for '{mode}' CPU mode.");
+           }
+        }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotBrowser))]
         public void ExceptionsCount()

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.FreeBSD.cs

@@ -34,6 +34,11 @@ public TimeSpan TotalProcessorTime
         {
             get
             {
+                if (IsCurrentProcess)
+                {
+                    return Environment.CpuUsage.TotalTime;
+                }
+
                 EnsureState(State.HaveNonExitedId);
                 Interop.Process.proc_stats stat = Interop.Process.GetThreadInfo(_processId, 0);
                 return Process.TicksToTimeSpan(stat.userTime + stat.systemTime);
@@ -51,6 +56,11 @@ public TimeSpan UserProcessorTime
         {
             get
             {
+                if (IsCurrentProcess)
+                {
+                    return Environment.CpuUsage.UserTime;
+                }
+
                 EnsureState(State.HaveNonExitedId);
 
                 Interop.Process.proc_stats stat = Interop.Process.GetThreadInfo(_processId, 0);
@@ -66,6 +76,11 @@ public TimeSpan PrivilegedProcessorTime
         {
             get
             {
+                if (IsCurrentProcess)
+                {
+                    return Environment.CpuUsage.PrivilegedTime;
+                }
+
                 EnsureState(State.HaveNonExitedId);
 
                 Interop.Process.proc_stats stat = Interop.Process.GetThreadInfo(_processId, 0);

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.Linux.cs

@@ -53,10 +53,7 @@ public static Process[] GetProcessesByName(string? processName, string machineNa
         [SupportedOSPlatform("maccatalyst")]
         public TimeSpan PrivilegedProcessorTime
         {
-            get
-            {
-                return TicksToTimeSpan(GetStat().stime);
-            }
+            get => IsCurrentProcess ? Environment.CpuUsage.PrivilegedTime : TicksToTimeSpan(GetStat().stime);
         }
 
         /// <summary>Gets the time the associated process was started.</summary>
@@ -132,6 +129,11 @@ public TimeSpan TotalProcessorTime
         {
             get
             {
+                if (IsCurrentProcess)
+                {
+                    return Environment.CpuUsage.TotalTime;
+                }
+
                 Interop.procfs.ParsedStat stat = GetStat();
                 return TicksToTimeSpan(stat.utime + stat.stime);
             }
@@ -146,10 +148,7 @@ public TimeSpan TotalProcessorTime
         [SupportedOSPlatform("maccatalyst")]
         public TimeSpan UserProcessorTime
         {
-            get
-            {
-                return TicksToTimeSpan(GetStat().utime);
-            }
+            get => IsCurrentProcess ? Environment.CpuUsage.UserTime : TicksToTimeSpan(GetStat().utime);
         }
 
         partial void EnsureHandleCountPopulated()

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs

@@ -22,6 +22,11 @@ public TimeSpan PrivilegedProcessorTime
         {
             get
             {
+                if (IsCurrentProcess)
+                {
+                    return Environment.CpuUsage.PrivilegedTime;
+                }
+
                 EnsureState(State.HaveNonExitedId);
                 Interop.libproc.rusage_info_v3 info = Interop.libproc.proc_pid_rusage(_processId);
                 return MapTime(info.ri_system_time);
@@ -64,6 +69,11 @@ public TimeSpan TotalProcessorTime
         {
             get
             {
+                if (IsCurrentProcess)
+                {
+                    return Environment.CpuUsage.TotalTime;
+                }
+
                 EnsureState(State.HaveNonExitedId);
                 Interop.libproc.rusage_info_v3 info = Interop.libproc.proc_pid_rusage(_processId);
                 return MapTime(info.ri_system_time + info.ri_user_time);
@@ -81,6 +91,11 @@ public TimeSpan UserProcessorTime
         {
             get
             {
+                if (IsCurrentProcess)
+                {
+                    return Environment.CpuUsage.UserTime;
+                }
+
                 EnsureState(State.HaveNonExitedId);
                 Interop.libproc.rusage_info_v3 info = Interop.libproc.proc_pid_rusage(_processId);
                 return MapTime(info.ri_user_time);

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.Windows.cs

@@ -232,7 +232,7 @@ private DateTime ExitTimeCore
         [SupportedOSPlatform("maccatalyst")]
         public TimeSpan PrivilegedProcessorTime
         {
-            get { return GetProcessTimes().PrivilegedProcessorTime; }
+            get => IsCurrentProcess ? Environment.CpuUsage.PrivilegedTime : GetProcessTimes().PrivilegedProcessorTime;
         }
 
         /// <summary>Gets the time the associated process was started.</summary>
@@ -251,7 +251,7 @@ internal DateTime StartTimeCore
         [SupportedOSPlatform("maccatalyst")]
         public TimeSpan TotalProcessorTime
         {
-            get { return GetProcessTimes().TotalProcessorTime; }
+            get => IsCurrentProcess ? Environment.CpuUsage.TotalTime : GetProcessTimes().TotalProcessorTime;
         }
 
         /// <summary>
@@ -263,7 +263,7 @@ public TimeSpan TotalProcessorTime
         [SupportedOSPlatform("maccatalyst")]
         public TimeSpan UserProcessorTime
         {
-            get { return GetProcessTimes().UserProcessorTime; }
+            get => IsCurrentProcess ? Environment.CpuUsage.UserTime : GetProcessTimes().UserProcessorTime;
         }
 
         /// <summary>

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.cs

@@ -1106,6 +1106,8 @@ public static Process[] GetProcesses(string machineName)
             return processes;
         }
 
+        private bool IsCurrentProcess => _processId == Environment.ProcessId;
+
         /// <devdoc>
         ///    <para>
         ///       Returns a new <see cref='System.Diagnostics.Process'/>

src/libraries/System.Private.CoreLib/src/System/Environment.UnixOrBrowser.cs

@@ -5,6 +5,7 @@
 using System.IO;
 using System.Reflection;
 using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
 using System.Text;
 using System.Threading;
 
@@ -69,5 +70,28 @@ private static int CheckedSysConf(Interop.Sys.SysConfName name)
             }
             return (int)result;
         }
+
+        /// <summary>
+        /// Get the CPU usage, including the process time spent running the application code, the process time spent running the operating system code,
+        /// and the total time spent running both the application and operating system code.
+        /// </summary>
+        [SupportedOSPlatform("maccatalyst")]
+        [UnsupportedOSPlatform("ios")]
+        [UnsupportedOSPlatform("tvos")]
+        [UnsupportedOSPlatform("browser")]
+        public static ProcessCpuUsage CpuUsage
+        {
+            get
+            {
+                Interop.Sys.ProcessCpuInformation cpuInfo = default;
+                Interop.Sys.GetCpuUtilization(ref cpuInfo);
+
+                // Division by 100 is to convert the nanoseconds to 100-nanoseconds to match .NET time units (100-nanoseconds).
+                ulong userTime100Nanoseconds = Math.Min(cpuInfo.lastRecordedUserTime / 100, (ulong)long.MaxValue);
+                ulong kernelTime100Nanoseconds = Math.Min(cpuInfo.lastRecordedKernelTime / 100, (ulong)long.MaxValue);
+
+                return new ProcessCpuUsage { UserTime = new TimeSpan((long)userTime100Nanoseconds), PrivilegedTime = new TimeSpan((long)kernelTime100Nanoseconds) };
+            }
+        }
     }
 }

src/libraries/System.Private.CoreLib/src/System/Environment.Windows.cs

@@ -6,6 +6,7 @@
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
 using System.Text;
 using Microsoft.Win32.SafeHandles;
 
@@ -358,5 +359,20 @@ private static unsafe string[] SegmentCommandLine(char* cmdLine)
 
             return arrayBuilder.ToArray();
         }
+
+        /// <summary>
+        /// Get the CPU usage, including the process time spent running the application code, the process time spent running the operating system code,
+        /// and the total time spent running both the application and operating system code.
+        /// </summary>
+        [SupportedOSPlatform("maccatalyst")]
+        [UnsupportedOSPlatform("ios")]
+        [UnsupportedOSPlatform("tvos")]
+        [UnsupportedOSPlatform("browser")]
+        public static ProcessCpuUsage CpuUsage
+        {
+            get => Interop.Kernel32.GetProcessTimes(Interop.Kernel32.GetCurrentProcess(), out _, out _, out long procKernelTime, out long procUserTime) ?
+                    new ProcessCpuUsage { UserTime = new TimeSpan(procUserTime), PrivilegedTime = new TimeSpan(procKernelTime) } :
+                    new ProcessCpuUsage { UserTime = TimeSpan.Zero, PrivilegedTime = TimeSpan.Zero };
+        }
     }
 }