GetTotalPauseDuration implementation (#68835)

src/coreclr/System.Private.CoreLib/src/System/GC.cs

@@ -719,5 +719,13 @@ public static T[] AllocateArray<T>(int length, bool pinned = false) // T[] rathe
 
             return Unsafe.As<T[]>(AllocateNewArray(typeof(T[]).TypeHandle.Value, length, flags));
         }
+
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        private static extern long _GetTotalPauseDuration();
+
+        public static TimeSpan GetTotalPauseDuration()
+        {
+            return new TimeSpan(_GetTotalPauseDuration());
+        }
     }
 }

src/coreclr/gc/gc.cpp

@@ -45045,6 +45045,11 @@ void GCHeap::GetMemoryInfo(uint64_t* highMemLoadThresholdBytes,
 #endif //_DEBUG
 }
 
+int64_t GCHeap::GetTotalPauseDuration()
+{
+    return (int64_t)(gc_heap::total_suspended_time * 10);
+}
+
 uint32_t GCHeap::GetMemoryLoad()
 {
     uint32_t memory_load = 0;

src/coreclr/gc/gcimpl.h

@@ -180,7 +180,9 @@ class GCHeap : public IGCHeapInternal
                        bool* isConcurrent,
                        uint64_t* genInfoRaw,
                        uint64_t* pauseInfoRaw,
-                       int kind);;
+                       int kind);
+
+    int64_t GetTotalPauseDuration();
 
     uint32_t GetMemoryLoad();
 

src/coreclr/gc/gcinterface.h

@@ -925,6 +925,9 @@ class IGCHeap {
 
     IGCHeap() {}
     virtual ~IGCHeap() {}
+
+    // Get the total paused duration
+    virtual int64_t GetTotalPauseDuration() = 0;
 };
 
 #ifdef WRITE_BARRIER_CHECK

src/coreclr/vm/comutilnative.cpp

@@ -674,6 +674,16 @@ UINT64   GCInterface::m_remPressure[MEM_PRESSURE_COUNT] = {0, 0, 0, 0};   // his
 // (m_iteration % MEM_PRESSURE_COUNT) is used as an index into m_addPressure and m_remPressure
 UINT     GCInterface::m_iteration = 0;
 
+FCIMPL0(INT64, GCInterface::GetTotalPauseDuration)
+{
+    FCALL_CONTRACT;
+
+    FC_GC_POLL_NOT_NEEDED();
+
+    return GCHeapUtilities::GetGCHeap()->GetTotalPauseDuration();
+}
+FCIMPLEND
+
 FCIMPL2(void, GCInterface::GetMemoryInfo, Object* objUNSAFE, int kind)
 {
     FCALL_CONTRACT;

src/coreclr/vm/comutilnative.h

@@ -143,6 +143,7 @@ class GCInterface {
     static FORCEINLINE UINT64 InterlockedAdd(UINT64 *pAugend, UINT64 addend);
     static FORCEINLINE UINT64 InterlockedSub(UINT64 *pMinuend, UINT64 subtrahend);
 
+    static FCDECL0(INT64,   GetTotalPauseDuration);
     static FCDECL2(void,    GetMemoryInfo, Object* objUNSAFE, int kind);
     static FCDECL0(UINT32,  GetMemoryLoad);
     static FCDECL0(int,     GetGcLatencyMode);

src/coreclr/vm/ecalllist.h

@@ -706,6 +706,7 @@ FCFuncStart(gGCInterfaceFuncs)
     FCFuncElement("_WaitForFullGCComplete", GCInterface::WaitForFullGCComplete)
     FCFuncElement("_CollectionCount", GCInterface::CollectionCount)
     FCFuncElement("GetMemoryInfo", GCInterface::GetMemoryInfo)
+    FCFuncElement("_GetTotalPauseDuration", GCInterface::GetTotalPauseDuration)
     FCFuncElement("GetMemoryLoad", GCInterface::GetMemoryLoad)
     QCFuncElement("_StartNoGCRegion", GCInterface::StartNoGCRegion)
     QCFuncElement("_EndNoGCRegion", GCInterface::EndNoGCRegion)

src/libraries/System.Runtime/src/MatchingRefApiCompatBaseline.txt

@@ -24,4 +24,5 @@ CannotMakeMemberAbstract : Member 'public System.Boolean System.IO.FileSystemInf
 CannotMakeMemberAbstract : Member 'public System.String System.IO.FileSystemInfo.Name.get()' is abstract in the reference but is not abstract in the implementation.
 # C# generates backing fields for fixed buffers as public.
 TypesMustExist : Type 'System.IO.Enumeration.FileSystemEntry.<_fileNameBuffer>e__FixedBuffer' does not exist in the reference but it does exist in the implementation.
-
+# This API only exists on servicing builds after the commit that introduce it
+MembersMustExist : Member 'public System.TimeSpan System.GC.GetTotalPauseDuration()' does not exist in the reference but it does exist in the implementation.

src/mono/System.Private.CoreLib/src/System/GC.Mono.cs

@@ -313,5 +313,10 @@ internal static int GetLastGCPercentTimeInGC()
         {
             return (int)EventPipeInternal.GetRuntimeCounterValue(EventPipeInternal.RuntimeCounters.GC_LAST_PERCENT_TIME_IN_GC);
         }
+
+        public static TimeSpan GetTotalPauseDuration()
+        {
+            return TimeSpan.Zero;
+        }
     }
 }

src/tests/GC/API/GC/GetTotalPauseDuration.cs

@@ -0,0 +1,36 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// Tests GC.GetTotalPauseDuration()
+
+using System;
+using System.Diagnostics;
+using System.Reflection;
+
+public class Test_Collect
+{
+    public static int Main()
+    {
+        Stopwatch sw = Stopwatch.StartNew();
+        GC.Collect();
+        sw.Stop();
+        TimeSpan elapsed = sw.Elapsed;
+        TimeSpan totalPauseDuration = (TimeSpan)typeof(GC).GetMethod("GetTotalPauseDuration", BindingFlags.Public | BindingFlags.Static).Invoke(null, null);
+        GCMemoryInfo memoryInfo = GC.GetGCMemoryInfo();
+        TimeSpan lastGcDuration = memoryInfo.PauseDurations[0];
+
+        // These conditions assume the only GC in the process 
+        // is the one we just triggered. This makes the test incompatible 
+        // with any changes that might introduce extra GCs.
+
+        if (TimeSpan.Zero < totalPauseDuration &&
+            totalPauseDuration <= elapsed &&
+            lastGcDuration == totalPauseDuration)
+        {
+            return 100;
+        }
+        else
+        {
+            return 101;
+        }
+    }
+}

src/tests/GC/API/GC/GetTotalPauseDuration.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <!-- Consider enable it for Mono whenever the implementation is ready -->
+    <CLRTestTargetUnsupported Condition="'$(RuntimeFlavor)' != 'coreclr'">true</CLRTestTargetUnsupported>
+    <!-- Temporaily set to P0 so that it runs on CI for initial testing -->
+    <CLRTestPriority>0</CLRTestPriority>
+  </PropertyGroup>
+  <PropertyGroup>
+    <!-- Set to 'Full' if the Debug? column is marked in the spreadsheet. Leave blank otherwise. -->
+    <DebugType>PdbOnly</DebugType>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="GetTotalPauseDuration.cs" />
+  </ItemGroup>
+</Project>