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Add work item dumping support to SOS' ThreadPool command (dotnet#20872)
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Adds a -wi switch to the ThreadPool command that will enumerate all queues dumping out all found work items.
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@stephentoub
stephentoub authored Nov 8, 2018
1 parent c60869f commit d793aa3
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Showing 4 changed files with 165 additions and 14 deletions.
2 changes: 1 addition & 1 deletion src/System.Private.CoreLib/shared/System/Collections/Concurrent/ConcurrentQueue.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ public class ConcurrentQueue<T> : IProducerConsumerCollection<T>, IReadOnlyColle
/// <summary>The current tail segment.</summary>
private volatile ConcurrentQueueSegment<T> _tail;
/// <summary>The current head segment.</summary>
private volatile ConcurrentQueueSegment<T> _head;
private volatile ConcurrentQueueSegment<T> _head; // SOS's ThreadPool command depends on this name

/// <summary>
/// Initializes a new instance of the <see cref="ConcurrentQueue{T}"/> class.
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6 changes: 3 additions & 3 deletions src/System.Private.CoreLib/shared/System/Collections/Concurrent/ConcurrentQueueSegment.cs
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Expand Up @@ -20,7 +20,7 @@ internal sealed class ConcurrentQueueSegment<T>
// http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue

/// <summary>The array of items in this queue. Each slot contains the item in that slot and its "sequence number".</summary>
internal readonly Slot[] _slots;
internal readonly Slot[] _slots; // SOS's ThreadPool command depends on this name
/// <summary>Mask for quickly accessing a position within the queue's array.</summary>
internal readonly int _slotsMask;
/// <summary>The head and tail positions, with padding to help avoid false sharing contention.</summary>
Expand All @@ -33,7 +33,7 @@ internal sealed class ConcurrentQueueSegment<T>
internal bool _frozenForEnqueues;
#pragma warning disable 0649 // some builds don't assign to this field
/// <summary>The segment following this one in the queue, or null if this segment is the last in the queue.</summary>
internal ConcurrentQueueSegment<T> _nextSegment;
internal ConcurrentQueueSegment<T> _nextSegment; // SOS's ThreadPool command depends on this name
#pragma warning restore 0649

/// <summary>Creates the segment.</summary>
Expand Down Expand Up @@ -315,7 +315,7 @@ public bool TryEnqueue(T item)
internal struct Slot
{
/// <summary>The item.</summary>
public T Item;
public T Item; // SOS's ThreadPool command depends on this being at the beginning of the struct when T is a reference type
/// <summary>The sequence number for this slot, used to synchronize between enqueuers and dequeuers.</summary>
public int SequenceNumber;
}
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12 changes: 6 additions & 6 deletions src/System.Private.CoreLib/src/System/Threading/ThreadPool.cs
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Expand Up @@ -110,7 +110,7 @@ public static void Remove(WorkStealingQueue queue)
internal sealed class WorkStealingQueue
{
private const int INITIAL_SIZE = 32;
internal volatile object[] m_array = new object[INITIAL_SIZE];
internal volatile object[] m_array = new object[INITIAL_SIZE]; // SOS's ThreadPool command depends on this name
private volatile int m_mask = INITIAL_SIZE - 1;

#if DEBUG
Expand Down Expand Up @@ -377,7 +377,7 @@ public object TrySteal(ref bool missedSteal)
}

internal bool loggingEnabled;
internal readonly ConcurrentQueue<object> workItems = new ConcurrentQueue<object>();
internal readonly ConcurrentQueue<object> workItems = new ConcurrentQueue<object>(); // SOS's ThreadPool command depends on this name

private Internal.PaddingFor32 pad1;

Expand Down Expand Up @@ -933,7 +933,7 @@ public virtual void Execute()

internal sealed class QueueUserWorkItemCallback : QueueUserWorkItemCallbackBase
{
private WaitCallback _callback;
private WaitCallback _callback; // SOS's ThreadPool command depends on this name
private readonly object _state;
private readonly ExecutionContext _context;

Expand Down Expand Up @@ -972,7 +972,7 @@ public override void Execute()

internal sealed class QueueUserWorkItemCallback<TState> : QueueUserWorkItemCallbackBase
{
private Action<TState> _callback;
private Action<TState> _callback; // SOS's ThreadPool command depends on this name
private readonly TState _state;
private readonly ExecutionContext _context;

Expand Down Expand Up @@ -1011,7 +1011,7 @@ public override void Execute()

internal sealed class QueueUserWorkItemCallbackDefaultContext : QueueUserWorkItemCallbackBase
{
private WaitCallback _callback;
private WaitCallback _callback; // SOS's ThreadPool command depends on this name
private readonly object _state;

internal static readonly ContextCallback s_executionContextShim = state =>
Expand All @@ -1038,7 +1038,7 @@ public override void Execute()

internal sealed class QueueUserWorkItemCallbackDefaultContext<TState> : QueueUserWorkItemCallbackBase
{
private Action<TState> _callback;
private Action<TState> _callback; // SOS's ThreadPool command depends on this name
private readonly TState _state;

internal static readonly ContextCallback s_executionContextShim = state =>
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159 changes: 155 additions & 4 deletions src/ToolBox/SOS/Strike/strike.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4518,8 +4518,7 @@ DECLARE_API(DumpAsync)
int offset = GetObjFieldOffset(ar.Address, ar.MT, W("m_stateFlags"), TRUE, &stateFlagsField);
if (offset != 0)
{
sos::Object obj = TO_TADDR(ar.Address);
MOVE(ar.TaskStateFlags, obj.GetAddress() + offset);
MOVE(ar.TaskStateFlags, ar.Address + offset);
}

// Get the async state machine object's StateMachine field.
Expand Down Expand Up @@ -8161,18 +8160,24 @@ DECLARE_API(ThreadPool)

if ((Status = threadpool.Request(g_sos)) == S_OK)
{
BOOL doHCDump = FALSE;
BOOL doHCDump = FALSE, doWorkItemDump = FALSE, dml = FALSE;

CMDOption option[] =
{ // name, vptr, type, hasValue
{"-ti", &doHCDump, COBOOL, FALSE}
{"-ti", &doHCDump, COBOOL, FALSE},
{"-wi", &doWorkItemDump, COBOOL, FALSE},
#ifndef FEATURE_PAL
{"/d", &dml, COBOOL, FALSE},
#endif
};

if (!GetCMDOption(args, option, _countof(option), NULL, 0, NULL))
{
return Status;
}

EnableDMLHolder dmlHolder(dml);

ExtOut ("CPU utilization: %d%%\n", threadpool.cpuUtilization);
ExtOut ("Worker Thread:");
ExtOut (" Total: %d", threadpool.NumWorkingWorkerThreads + threadpool.NumIdleWorkerThreads + threadpool.NumRetiredWorkerThreads);
Expand Down Expand Up @@ -8215,6 +8220,152 @@ DECLARE_API(ThreadPool)
workRequestPtr = workRequestData.NextWorkRequest;
}

if (doWorkItemDump && g_snapshot.Build())
{
// Display a message if the heap isn't verified.
sos::GCHeap gcheap;
if (!gcheap.AreGCStructuresValid())
{
DisplayInvalidStructuresMessage();
}

// Walk every heap item looking for the global queue and local queues.
ExtOut("\nQueued work items:\n%" POINTERSIZE "s %" POINTERSIZE "s %s\n", "Queue", "Address", "Work Item");
HeapStat stats;
for (sos::ObjectIterator itr = gcheap.WalkHeap(); !IsInterrupt() && itr != NULL; ++itr)
{
if (_wcscmp(itr->GetTypeName(), W("System.Threading.ThreadPoolWorkQueue")) == 0)
{
// We found a global queue (there should be only one, given one AppDomain).
// Get its workItems ConcurrentQueue<IThreadPoolWorkItem>.
int offset = GetObjFieldOffset(itr->GetAddress(), itr->GetMT(), W("workItems"));
if (offset > 0)
{
DWORD_PTR workItemsConcurrentQueuePtr;
MOVE(workItemsConcurrentQueuePtr, itr->GetAddress() + offset);
if (sos::IsObject(workItemsConcurrentQueuePtr, false))
{
// We got the ConcurrentQueue. Get its head segment.
sos::Object workItemsConcurrentQueue = TO_TADDR(workItemsConcurrentQueuePtr);
offset = GetObjFieldOffset(workItemsConcurrentQueue.GetAddress(), workItemsConcurrentQueue.GetMT(), W("_head"));
if (offset > 0)
{
// Now, walk from segment to segment, each of which contains an array of work items.
DWORD_PTR segmentPtr;
MOVE(segmentPtr, workItemsConcurrentQueue.GetAddress() + offset);
while (sos::IsObject(segmentPtr, false))
{
sos::Object segment = TO_TADDR(segmentPtr);

// Get the work items array. It's an array of Slot structs, which starts with the T.
offset = GetObjFieldOffset(segment.GetAddress(), segment.GetMT(), W("_slots"));
if (offset <= 0)
{
break;
}

DWORD_PTR slotsPtr;
MOVE(slotsPtr, segment.GetAddress() + offset);
if (!sos::IsObject(slotsPtr, false))
{
break;
}

// Walk every element in the array, outputting details on non-null work items.
DacpObjectData slotsArray;
if (slotsArray.Request(g_sos, TO_CDADDR(slotsPtr)) == S_OK && slotsArray.ObjectType == OBJ_ARRAY)
{
for (int i = 0; i < slotsArray.dwNumComponents; i++)
{
CLRDATA_ADDRESS workItemPtr;
MOVE(workItemPtr, TO_CDADDR(slotsArray.ArrayDataPtr + (i * slotsArray.dwComponentSize))); // the item object reference is at the beginning of the Slot
if (workItemPtr != NULL && sos::IsObject(workItemPtr, false))
{
sos::Object workItem = TO_TADDR(workItemPtr);
stats.Add((DWORD_PTR)workItem.GetMT(), (DWORD)workItem.GetSize());
DMLOut("%" POINTERSIZE "s %s %S", "[Global]", DMLObject(workItem.GetAddress()), workItem.GetTypeName());
if ((offset = GetObjFieldOffset(workItem.GetAddress(), workItem.GetMT(), W("_callback"))) > 0 ||
(offset = GetObjFieldOffset(workItem.GetAddress(), workItem.GetMT(), W("m_action"))) > 0)
{
CLRDATA_ADDRESS delegatePtr;
MOVE(delegatePtr, workItem.GetAddress() + offset);
CLRDATA_ADDRESS md;
if (TryGetMethodDescriptorForDelegate(delegatePtr, &md))
{
NameForMD_s((DWORD_PTR)md, g_mdName, mdNameLen);
ExtOut(" => %S", g_mdName);
}
}
ExtOut("\n");
}
}
}

// Move to the next segment.
DacpFieldDescData segmentField;
offset = GetObjFieldOffset(segment.GetAddress(), segment.GetMT(), W("_nextSegment"), TRUE, &segmentField);
if (offset <= 0)
{
break;
}

MOVE(segmentPtr, segment.GetAddress() + offset);
if (segmentPtr == NULL)
{
break;
}
}
}
}
}
}
else if (_wcscmp(itr->GetTypeName(), W("System.Threading.ThreadPoolWorkQueue+WorkStealingQueue")) == 0)
{
// We found a local queue. Get its work items array.
int offset = GetObjFieldOffset(itr->GetAddress(), itr->GetMT(), W("m_array"));
if (offset > 0)
{
// Walk every element in the array, outputting details on non-null work items.
DWORD_PTR workItemArrayPtr;
MOVE(workItemArrayPtr, itr->GetAddress() + offset);
DacpObjectData workItemArray;
if (workItemArray.Request(g_sos, TO_CDADDR(workItemArrayPtr)) == S_OK && workItemArray.ObjectType == OBJ_ARRAY)
{
for (int i = 0; i < workItemArray.dwNumComponents; i++)
{
CLRDATA_ADDRESS workItemPtr;
MOVE(workItemPtr, TO_CDADDR(workItemArray.ArrayDataPtr + (i * workItemArray.dwComponentSize)));
if (workItemPtr != NULL && sos::IsObject(workItemPtr, false))
{
sos::Object workItem = TO_TADDR(workItemPtr);
stats.Add((DWORD_PTR)workItem.GetMT(), (DWORD)workItem.GetSize());
DMLOut("%s %s %S", DMLObject(itr->GetAddress()), DMLObject(workItem.GetAddress()), workItem.GetTypeName());
if ((offset = GetObjFieldOffset(workItem.GetAddress(), workItem.GetMT(), W("_callback"))) > 0 ||
(offset = GetObjFieldOffset(workItem.GetAddress(), workItem.GetMT(), W("m_action"))) > 0)
{
CLRDATA_ADDRESS delegatePtr;
MOVE(delegatePtr, workItem.GetAddress() + offset);
CLRDATA_ADDRESS md;
if (TryGetMethodDescriptorForDelegate(delegatePtr, &md))
{
NameForMD_s((DWORD_PTR)md, g_mdName, mdNameLen);
ExtOut(" => %S", g_mdName);
}
}
ExtOut("\n");
}
}
}
}
}
}

// Output a summary.
stats.Sort();
stats.Print();
ExtOut("\n");
}

if (doHCDump)
{
ExtOut ("--------------------------------------\n");
Expand Down

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