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|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
/*++
Module Name:
Win32ThreadPool.h
Abstract:
This module is the header file for thread pools using Win32 APIs.
Revision History:
--*/
#ifndef _WIN32THREADPOOL_H
#define _WIN32THREADPOOL_H
#include "delegateinfo.h"
#include "util.hpp"
#include "nativeoverlapped.h"
#include "hillclimbing.h"
#define MAX_WAITHANDLES 64
#define MAX_CACHED_EVENTS 40 // upper limit on number of wait events cached
#define WAIT_REGISTERED 0x01
#define WAIT_ACTIVE 0x02
#define WAIT_DELETE 0x04
#define TIMER_REGISTERED 0x01
#define TIMER_ACTIVE 0x02
#define TIMER_DELETE 0x04
#define WAIT_SINGLE_EXECUTION 0x00000001
#define WAIT_FREE_CONTEXT 0x00000002
#define WAIT_INTERNAL_COMPLETION 0x00000004
#define QUEUE_ONLY 0x00000000 // do not attempt to call on the thread
#define CALL_OR_QUEUE 0x00000001 // call on the same thread if not too busy, else queue
const int MaxLimitThreadsPerCPU=250; // upper limit on number of cp threads per CPU
const int MaxFreeCPThreadsPerCPU=2; // upper limit on number of free cp threads per CPU
const int CpuUtilizationHigh=95; // remove threads when above this
const int CpuUtilizationLow =80; // inject more threads if below this
#ifndef FEATURE_PAL
extern HANDLE (WINAPI *g_pufnCreateIoCompletionPort)(HANDLE FileHandle,
HANDLE ExistingCompletionPort,
ULONG_PTR CompletionKey,
DWORD NumberOfConcurrentThreads);
extern int (WINAPI *g_pufnNtQueryInformationThread) (HANDLE ThreadHandle,
THREADINFOCLASS ThreadInformationClass,
PVOID ThreadInformation,
ULONG ThreadInformationLength,
PULONG ReturnLength);
extern int (WINAPI * g_pufnNtQuerySystemInformation) (SYSTEM_INFORMATION_CLASS SystemInformationClass,
PVOID SystemInformation,
ULONG SystemInformationLength,
PULONG ReturnLength OPTIONAL);
#endif // !FEATURE_PAL
#define FILETIME_TO_INT64(t) (*(__int64*)&(t))
#define MILLI_TO_100NANO(x) (x * 10000) // convert from milliseond to 100 nanosecond unit
/**
* This type is supposed to be private to ThreadpoolMgr.
* It's at global scope because Strike needs to be able to access its
* definition.
*/
struct WorkRequest {
WorkRequest* next;
LPTHREAD_START_ROUTINE Function;
PVOID Context;
};
typedef struct _IOCompletionContext
{
DWORD ErrorCode;
DWORD numBytesTransferred;
LPOVERLAPPED lpOverlapped;
size_t key;
} IOCompletionContext, *PIOCompletionContext;
typedef DPTR(WorkRequest) PTR_WorkRequest;
class ThreadpoolMgr
{
friend class ClrDataAccess;
friend struct DelegateInfo;
friend class ThreadPoolNative;
friend class TimerNative;
friend class UnManagedPerAppDomainTPCount;
friend class ManagedPerAppDomainTPCount;
friend class PerAppDomainTPCountList;
friend class HillClimbing;
friend struct _DacGlobals;
//
// UnfairSemaphore is a more scalable semaphore than CLRSemaphore. It prefers to release threads that have more recently begun waiting,
// to preserve locality. Additionally, very recently-waiting threads can be released without an addition kernel transition to unblock
// them, which reduces latency.
//
// UnfairSemaphore is only appropriate in scenarios where the order of unblocking threads is not important, and where threads frequently
// need to be woken. This is true of the ThreadPool's "worker semaphore", but not, for example, of the "retired worker semaphore" which is
// only rarely signalled.
//
// A further optimization that could be done here would be to replace CLRSemaphore with a Win32 IO Completion Port. Completion ports
// unblock threads in LIFO order, unlike the roughly-FIFO ordering of ordinary semaphores, and that would help to keep the "warm" threads warm.
// We did not do this in CLR 4.0 because hosts currently have no way of intercepting calls to IO Completion Ports (other than THE completion port
// behind the I/O thread pool), and we did not have time to explore the implications of this. Also, completion ports are not available on the Mac,
// though Snow Leopard has something roughly similar (and a regular Semaphore would do on the Mac in a pinch).
//
class UnfairSemaphore
{
private:
// padding to ensure we get our own cache line
BYTE padding1[64];
//
// We track everything we care about in a single 64-bit struct to allow us to
// do CompareExchanges on this for atomic updates.
//
union Counts
{
struct
{
int spinners : 16; //how many threads are currently spin-waiting for this semaphore?
int countForSpinners : 16; //how much of the semaphore's count is availble to spinners?
int waiters : 16; //how many threads are blocked in the OS waiting for this semaphore?
int countForWaiters : 16; //how much count is available to waiters?
};
LONGLONG asLongLong;
} m_counts;
private:
const int m_spinLimitPerProcessor; //used when calculating max spin duration
CLRSemaphore m_sem; //waiters wait on this
// padding to ensure we get our own cache line
BYTE padding2[64];
INDEBUG(int m_maxCount;)
bool UpdateCounts(Counts newCounts, Counts currentCounts)
{
LIMITED_METHOD_CONTRACT;
Counts oldCounts;
oldCounts.asLongLong = FastInterlockCompareExchangeLong(&m_counts.asLongLong, newCounts.asLongLong, currentCounts.asLongLong);
if (oldCounts.asLongLong == currentCounts.asLongLong)
{
// we succesfully updated the counts. Now validate what we put in.
// Note: we can't validate these unless the CompareExchange succeeds, because
// on x86 a VolatileLoad of m_counts is not atomic; we could end up getting inconsistent
// values. It's not until we've successfully stored the new values that we know for sure
// that the old values were correct (because if they were not, the CompareExchange would have
// failed.
_ASSERTE(newCounts.spinners >= 0);
_ASSERTE(newCounts.countForSpinners >= 0);
_ASSERTE(newCounts.waiters >= 0);
_ASSERTE(newCounts.countForWaiters >= 0);
_ASSERTE(newCounts.countForSpinners + newCounts.countForWaiters <= m_maxCount);
return true;
}
else
{
// we lost a race with some other thread, and will need to try again.
return false;
}
}
public:
UnfairSemaphore(int maxCount, int spinLimitPerProcessor)
: m_spinLimitPerProcessor(spinLimitPerProcessor)
{
CONTRACTL
{
THROWS;
GC_NOTRIGGER;
SO_TOLERANT;
MODE_ANY;
}
CONTRACTL_END;
_ASSERTE(maxCount <= 0x7fff); //counts need to fit in signed 16-bit ints
INDEBUG(m_maxCount = maxCount;)
m_counts.asLongLong = 0;
m_sem.Create(0, maxCount);
}
//
// no destructor - CLRSemaphore will close itself in its own destructor.
//
//~UnfairSemaphore()
//{
//}
void Release(int countToRelease)
{
while (true)
{
Counts currentCounts, newCounts;
currentCounts.asLongLong = VolatileLoad(&m_counts.asLongLong);
newCounts = currentCounts;
int remainingCount = countToRelease;
// First, prefer to release existing spinners,
// because a) they're hot, and b) we don't need a kernel
// transition to release them.
int spinnersToRelease = max(0, min(remainingCount, currentCounts.spinners - currentCounts.countForSpinners));
newCounts.countForSpinners += spinnersToRelease;
remainingCount -= spinnersToRelease;
// Next, prefer to release existing waiters
int waitersToRelease = max(0, min(remainingCount, currentCounts.waiters - currentCounts.countForWaiters));
newCounts.countForWaiters += waitersToRelease;
remainingCount -= waitersToRelease;
// Finally, release any future spinners that might come our way
newCounts.countForSpinners += remainingCount;
// Try to commit the transaction
if (UpdateCounts(newCounts, currentCounts))
{
// Now we need to release the waiters we promised to release
if (waitersToRelease > 0)
{
LONG previousCount;
INDEBUG(BOOL success =) m_sem.Release((LONG)waitersToRelease, &previousCount);
_ASSERTE(success);
}
break;
}
}
}
bool Wait(DWORD timeout)
{
while (true)
{
Counts currentCounts, newCounts;
currentCounts.asLongLong = VolatileLoad(&m_counts.asLongLong);
newCounts = currentCounts;
// First, just try to grab some count.
if (currentCounts.countForSpinners > 0)
{
newCounts.countForSpinners--;
if (UpdateCounts(newCounts, currentCounts))
return true;
}
else
{
// No count available, become a spinner
newCounts.spinners++;
if (UpdateCounts(newCounts, currentCounts))
break;
}
}
//
// Now we're a spinner.
//
int numSpins = 0;
while (true)
{
Counts currentCounts, newCounts;
currentCounts.asLongLong = VolatileLoad(&m_counts.asLongLong);
newCounts = currentCounts;
if (currentCounts.countForSpinners > 0)
{
newCounts.countForSpinners--;
newCounts.spinners--;
if (UpdateCounts(newCounts, currentCounts))
return true;
}
else
{
double spinnersPerProcessor = (double)currentCounts.spinners / ThreadpoolMgr::NumberOfProcessors;
int spinLimit = (int)((m_spinLimitPerProcessor / spinnersPerProcessor) + 0.5);
if (numSpins >= spinLimit)
{
newCounts.spinners--;
newCounts.waiters++;
if (UpdateCounts(newCounts, currentCounts))
break;
}
else
{
//
// We yield to other threads using SleepEx rather than the more traditional SwitchToThread.
// This is because SwitchToThread does not yield to threads currently scheduled to run on other
// processors. On a 4-core machine, for example, this means that SwitchToThread is only ~25% likely
// to yield to the correct thread in some scenarios.
// SleepEx has the disadvantage of not yielding to lower-priority threads. However, this is ok because
// once we've called this a few times we'll become a "waiter" and wait on the CLRSemaphore, and that will
// yield to anything that is runnable.
//
ClrSleepEx(0, FALSE);
numSpins++;
}
}
}
//
// Now we're a waiter
//
DWORD result = m_sem.Wait(timeout, FALSE);
_ASSERTE(WAIT_OBJECT_0 == result || WAIT_TIMEOUT == result);
while (true)
{
Counts currentCounts, newCounts;
currentCounts.asLongLong = VolatileLoad(&m_counts.asLongLong);
newCounts = currentCounts;
newCounts.waiters--;
if (result == WAIT_OBJECT_0)
newCounts.countForWaiters--;
if (UpdateCounts(newCounts, currentCounts))
return (result == WAIT_OBJECT_0);
}
}
};
public:
struct ThreadCounter
{
static const int MaxPossibleCount = 0x7fff;
union Counts
{
struct
{
//
// Note: these are signed rather than unsigned to allow us to detect under/overflow.
//
int MaxWorking : 16; //Determined by HillClimbing; adjusted elsewhere for timeouts, etc.
int NumActive : 16; //Active means working or waiting on WorkerSemaphore. These are "warm/hot" threads.
int NumWorking : 16; //Trying to get work from various queues. Not waiting on either semaphore.
int NumRetired : 16; //Not trying to get work; waiting on RetiredWorkerSemaphore. These are "cold" threads.
// Note: the only reason we need "retired" threads at all is that it allows some threads to eventually time out
// even if other threads are getting work. If we ever make WorkerSemaphore a true LIFO semaphore, we will no longer
// need the concept of "retirement" - instead, the very "coldest" threads will naturally be the first to time out.
};
LONGLONG AsLongLong;
bool operator==(Counts other) {LIMITED_METHOD_CONTRACT; return AsLongLong == other.AsLongLong;}
} counts;
// padding to ensure we get our own cache line
BYTE padding[64];
Counts GetCleanCounts()
{
LIMITED_METHOD_CONTRACT;
#ifdef _WIN64
// VolatileLoad x64 bit read is atomic
return DangerousGetDirtyCounts();
#else // !_WIN64
// VolatileLoad may result in torn read
Counts result;
#ifndef DACCESS_COMPILE
result.AsLongLong = FastInterlockCompareExchangeLong(&counts.AsLongLong, 0, 0);
ValidateCounts(result);
#else
result.AsLongLong = 0; //prevents prefast warning for DAC builds
#endif
return result;
#endif // !_WIN64
}
//
// This does a non-atomic read of the counts. The returned value is suitable only
// for use inside of a read-compare-exchange loop, where the compare-exhcange must succeed
// before any action is taken. Use GetCleanWorkerCounts for other needs, but keep in mind
// it's much slower.
//
Counts DangerousGetDirtyCounts()
{
LIMITED_METHOD_CONTRACT;
Counts result;
#ifndef DACCESS_COMPILE
result.AsLongLong = VolatileLoad(&counts.AsLongLong);
#else
result.AsLongLong = 0; //prevents prefast warning for DAC builds
#endif
return result;
}
Counts CompareExchangeCounts(Counts newCounts, Counts oldCounts)
{
LIMITED_METHOD_CONTRACT;
Counts result;
#ifndef DACCESS_COMPILE
result.AsLongLong = FastInterlockCompareExchangeLong(&counts.AsLongLong, newCounts.AsLongLong, oldCounts.AsLongLong);
if (result == oldCounts)
{
// can only do validation on success; if we failed, it may have been due to a previous
// dirty read, which may contain invalid values.
ValidateCounts(result);
ValidateCounts(newCounts);
}
#else
result.AsLongLong = 0; //prevents prefast warning for DAC builds
#endif
return result;
}
private:
static void ValidateCounts(Counts counts)
{
LIMITED_METHOD_CONTRACT;
_ASSERTE(counts.MaxWorking > 0);
_ASSERTE(counts.NumActive >= 0);
_ASSERTE(counts.NumWorking >= 0);
_ASSERTE(counts.NumRetired >= 0);
_ASSERTE(counts.NumWorking <= counts.NumActive);
}
};
public:
static void ReportThreadStatus(bool isWorking);
// enumeration of different kinds of memory blocks that are recycled
enum MemType
{
MEMTYPE_AsyncCallback = 0,
MEMTYPE_DelegateInfo = 1,
MEMTYPE_WorkRequest = 2,
MEMTYPE_PostRequest = 3,
MEMTYPE_COUNT = 4,
};
static BOOL Initialize();
static BOOL SetMaxThreadsHelper(DWORD MaxWorkerThreads,
DWORD MaxIOCompletionThreads);
static BOOL SetMaxThreads(DWORD MaxWorkerThreads,
DWORD MaxIOCompletionThreads);
static BOOL GetMaxThreads(DWORD* MaxWorkerThreads,
DWORD* MaxIOCompletionThreads);
static BOOL SetMinThreads(DWORD MinWorkerThreads,
DWORD MinIOCompletionThreads);
static BOOL GetMinThreads(DWORD* MinWorkerThreads,
DWORD* MinIOCompletionThreads);
static BOOL GetAvailableThreads(DWORD* AvailableWorkerThreads,
DWORD* AvailableIOCompletionThreads);
static BOOL QueueUserWorkItem(LPTHREAD_START_ROUTINE Function,
PVOID Context,
ULONG Flags,
BOOL UnmanagedTPRequest=TRUE);
static BOOL PostQueuedCompletionStatus(LPOVERLAPPED lpOverlapped,
LPOVERLAPPED_COMPLETION_ROUTINE Function);
inline static BOOL IsCompletionPortInitialized()
{
LIMITED_METHOD_CONTRACT;
return GlobalCompletionPort != NULL;
}
static BOOL DrainCompletionPortQueue();
static BOOL RegisterWaitForSingleObject(PHANDLE phNewWaitObject,
HANDLE hWaitObject,
WAITORTIMERCALLBACK Callback,
PVOID Context,
ULONG timeout,
DWORD dwFlag);
static BOOL UnregisterWaitEx(HANDLE hWaitObject,HANDLE CompletionEvent);
static void WaitHandleCleanup(HANDLE hWaitObject);
static BOOL WINAPI BindIoCompletionCallback(HANDLE FileHandle,
LPOVERLAPPED_COMPLETION_ROUTINE Function,
ULONG Flags,
DWORD& errorCode);
static void WINAPI WaitIOCompletionCallback(DWORD dwErrorCode,
DWORD numBytesTransferred,
LPOVERLAPPED lpOverlapped);
static VOID WINAPI CallbackForInitiateDrainageOfCompletionPortQueue(
DWORD dwErrorCode,
DWORD dwNumberOfBytesTransfered,
LPOVERLAPPED lpOverlapped
);
static VOID WINAPI CallbackForContinueDrainageOfCompletionPortQueue(
DWORD dwErrorCode,
DWORD dwNumberOfBytesTransfered,
LPOVERLAPPED lpOverlapped
);
static BOOL SetAppDomainRequestsActive(BOOL UnmanagedTP = FALSE);
static void ClearAppDomainRequestsActive(BOOL UnmanagedTP = FALSE, BOOL AdUnloading = FALSE, LONG index = -1);
static inline void UpdateLastDequeueTime()
{
LIMITED_METHOD_CONTRACT;
VolatileStore(&LastDequeueTime, (unsigned int)GetTickCount());
}
static BOOL CreateTimerQueueTimer(PHANDLE phNewTimer,
WAITORTIMERCALLBACK Callback,
PVOID Parameter,
DWORD DueTime,
DWORD Period,
ULONG Flags);
static BOOL ChangeTimerQueueTimer(HANDLE Timer,
ULONG DueTime,
ULONG Period);
static BOOL DeleteTimerQueueTimer(HANDLE Timer,
HANDLE CompletionEvent);
static void RecycleMemory(LPVOID mem, enum MemType memType);
static void FlushQueueOfTimerInfos();
static BOOL HaveTimerInfosToFlush() { return TimerInfosToBeRecycled != NULL; }
inline static BOOL IsThreadPoolHosted()
{
return FALSE;
}
#ifndef FEATURE_PAL
static LPOVERLAPPED CompletionPortDispatchWorkWithinAppDomain(Thread* pThread, DWORD* pErrorCode, DWORD* pNumBytes, size_t* pKey, DWORD adid);
static void StoreOverlappedInfoInThread(Thread* pThread, DWORD dwErrorCode, DWORD dwNumBytes, size_t key, LPOVERLAPPED lpOverlapped);
#endif // !FEATURE_PAL
// Enable filtering of correlation ETW events for cases handled at a higher abstraction level
#ifndef DACCESS_COMPILE
static FORCEINLINE BOOL AreEtwQueueEventsSpeciallyHandled(LPTHREAD_START_ROUTINE Function)
{
// Timer events are handled at a higher abstraction level: in the managed Timer class
return (Function == ThreadpoolMgr::AsyncTimerCallbackCompletion);
}
static FORCEINLINE BOOL AreEtwIOQueueEventsSpeciallyHandled(LPOVERLAPPED_COMPLETION_ROUTINE Function)
{
// We ignore drainage events b/c they are uninteresting
// We handle registered waits at a higher abstraction level
return (Function == ThreadpoolMgr::CallbackForInitiateDrainageOfCompletionPortQueue
|| Function == ThreadpoolMgr::CallbackForContinueDrainageOfCompletionPortQueue
|| Function == ThreadpoolMgr::WaitIOCompletionCallback);
}
#endif
private:
#ifndef DACCESS_COMPILE
inline static void FreeWorkRequest(WorkRequest* workRequest)
{
RecycleMemory( workRequest, MEMTYPE_WorkRequest ); //delete workRequest;
}
inline static WorkRequest* MakeWorkRequest(LPTHREAD_START_ROUTINE function, PVOID context)
{
CONTRACTL
{
THROWS;
GC_NOTRIGGER;
MODE_ANY;
}
CONTRACTL_END;;
WorkRequest* wr = (WorkRequest*) GetRecycledMemory(MEMTYPE_WorkRequest);
_ASSERTE(wr);
if (NULL == wr)
return NULL;
wr->Function = function;
wr->Context = context;
wr->next = NULL;
return wr;
}
struct PostRequest {
LPOVERLAPPED_COMPLETION_ROUTINE Function;
DWORD errorCode;
DWORD numBytesTransferred;
LPOVERLAPPED lpOverlapped;
};
inline static PostRequest* MakePostRequest(LPOVERLAPPED_COMPLETION_ROUTINE function, LPOVERLAPPED overlapped)
{
CONTRACTL
{
THROWS;
GC_NOTRIGGER;
MODE_ANY;
}
CONTRACTL_END;;
PostRequest* pr = (PostRequest*) GetRecycledMemory(MEMTYPE_PostRequest);
_ASSERTE(pr);
if (NULL == pr)
return NULL;
pr->Function = function;
pr->errorCode = 0;
pr->numBytesTransferred = 0;
pr->lpOverlapped = overlapped;
return pr;
}
inline static void ReleasePostRequest(PostRequest *postRequest)
{
WRAPPER_NO_CONTRACT;
ThreadpoolMgr::RecycleMemory(postRequest, MEMTYPE_PostRequest);
}
typedef Wrapper< PostRequest *, DoNothing<PostRequest *>, ThreadpoolMgr::ReleasePostRequest > PostRequestHolder;
#endif // #ifndef DACCESS_COMPILE
typedef struct {
DWORD numBytes;
ULONG_PTR *key;
LPOVERLAPPED pOverlapped;
DWORD errorCode;
} QueuedStatus;
typedef DPTR(struct _LIST_ENTRY) PTR_LIST_ENTRY;
typedef struct _LIST_ENTRY {
struct _LIST_ENTRY *Flink;
struct _LIST_ENTRY *Blink;
} LIST_ENTRY, *PLIST_ENTRY;
struct WaitInfo;
typedef struct {
HANDLE threadHandle;
DWORD threadId;
CLREvent startEvent;
LONG NumWaitHandles; // number of wait objects registered to the thread <=64
LONG NumActiveWaits; // number of objects, thread is actually waiting on (this may be less than
// NumWaitHandles since the thread may not have activated some waits
HANDLE waitHandle[MAX_WAITHANDLES]; // array of wait handles (copied from waitInfo since
// we need them to be contiguous)
LIST_ENTRY waitPointer[MAX_WAITHANDLES]; // array of doubly linked list of corresponding waitinfo
} ThreadCB;
typedef struct {
ULONG startTime; // time at which wait was started
// endTime = startTime+timeout
ULONG remainingTime; // endTime - currentTime
} WaitTimerInfo;
struct WaitInfo {
LIST_ENTRY link; // Win9x does not allow duplicate waithandles, so we need to
// group all waits on a single waithandle using this linked list
HANDLE waitHandle;
WAITORTIMERCALLBACK Callback;
PVOID Context;
ULONG timeout;
WaitTimerInfo timer;
DWORD flag;
DWORD state;
ThreadCB* threadCB;
LONG refCount; // when this reaches 0, the waitInfo can be safely deleted
CLREvent PartialCompletionEvent; // used to synchronize deactivation of a wait
CLREvent InternalCompletionEvent; // only one of InternalCompletion or ExternalCompletion is used
// but I cant make a union since CLREvent has a non-default constructor
HANDLE ExternalCompletionEvent; // they are signalled when all callbacks have completed (refCount=0)
ADID handleOwningAD;
OBJECTHANDLE ExternalEventSafeHandle;
} ;
// structure used to maintain global information about wait threads. Protected by WaitThreadsCriticalSection
typedef struct WaitThreadTag {
LIST_ENTRY link;
ThreadCB* threadCB;
} WaitThreadInfo;
struct AsyncCallback{
WaitInfo* wait;
BOOL waitTimedOut;
} ;
#ifndef DACCESS_COMPILE
static VOID
AcquireAsyncCallback(AsyncCallback *pAsyncCB)
{
LIMITED_METHOD_CONTRACT;
}
static VOID
ReleaseAsyncCallback(AsyncCallback *pAsyncCB)
{
CONTRACTL
{
THROWS;
GC_TRIGGERS;
MODE_ANY;
}
CONTRACTL_END;
WaitInfo *waitInfo = pAsyncCB->wait;
ThreadpoolMgr::RecycleMemory((LPVOID*)pAsyncCB, ThreadpoolMgr::MEMTYPE_AsyncCallback);
// if this was a single execution, we now need to stop rooting registeredWaitHandle
// in a GC handle. This will cause the finalizer to pick it up and call the cleanup
// routine.
if ( (waitInfo->flag & WAIT_SINGLE_EXECUTION) && (waitInfo->flag & WAIT_FREE_CONTEXT))
{
DelegateInfo* pDelegate = (DelegateInfo*) waitInfo->Context;
_ASSERTE(pDelegate->m_registeredWaitHandle);
{
GCX_COOP();
AppDomainFromIDHolder ad(pDelegate->m_appDomainId, TRUE);
if (!ad.IsUnloaded())
// if no domain then handle already gone or about to go.
StoreObjectInHandle(pDelegate->m_registeredWaitHandle, NULL);
}
}
if (InterlockedDecrement(&waitInfo->refCount) == 0)
ThreadpoolMgr::DeleteWait(waitInfo);
}
typedef Holder<AsyncCallback *, ThreadpoolMgr::AcquireAsyncCallback, ThreadpoolMgr::ReleaseAsyncCallback> AsyncCallbackHolder;
inline static AsyncCallback* MakeAsyncCallback()
{
WRAPPER_NO_CONTRACT;
return (AsyncCallback*) GetRecycledMemory(MEMTYPE_AsyncCallback);
}
static VOID ReleaseInfo(OBJECTHANDLE& hndSafeHandle,
ADID& owningAD,
HANDLE hndNativeHandle)
{
CONTRACTL
{
NOTHROW;
MODE_ANY;
GC_TRIGGERS;
}
CONTRACTL_END
// Use of EX_TRY, GCPROTECT etc in the same function is causing prefast to complain about local variables with
// same name masking each other (#246). The error could not be suppressed with "#pragma PREFAST_SUPPRESS"
#ifndef _PREFAST_
if (hndSafeHandle != NULL)
{
SAFEHANDLEREF refSH = NULL;
GCX_COOP();
GCPROTECT_BEGIN(refSH);
{
EX_TRY
{
ENTER_DOMAIN_ID(owningAD);
{
// Read the GC handle
refSH = (SAFEHANDLEREF) ObjectToOBJECTREF(ObjectFromHandle(hndSafeHandle));
// Destroy the GC handle
DestroyHandle(hndSafeHandle);
if (refSH != NULL)
{
SafeHandleHolder h(&refSH);
HANDLE hEvent = refSH->GetHandle();
if (hEvent != INVALID_HANDLE_VALUE)
{
UnsafeSetEvent(hEvent);
}
}
}
END_DOMAIN_TRANSITION;
}
EX_CATCH
{
}
EX_END_CATCH(SwallowAllExceptions);
}
GCPROTECT_END();
hndSafeHandle = NULL;
owningAD = (ADID) 0;
}
#endif
}
#endif // #ifndef DACCESS_COMPILE
typedef struct {
LIST_ENTRY link;
HANDLE Handle;
} WaitEvent ;
// Timer
typedef struct {
LIST_ENTRY link; // doubly linked list of timers
ULONG FiringTime; // TickCount of when to fire next
WAITORTIMERCALLBACK Function; // Function to call when timer fires
PVOID Context; // Context to pass to function when timer fires
ULONG Period;
DWORD flag; // How do we deal with the context
DWORD state;
LONG refCount;
HANDLE ExternalCompletionEvent; // only one of this is used, but cant do a union since CLREvent has a non-default constructor
CLREvent InternalCompletionEvent; // flags indicates which one is being used
OBJECTHANDLE ExternalEventSafeHandle;
ADID handleOwningAD;
} TimerInfo;
static VOID AcquireWaitInfo(WaitInfo *pInfo)
{
}
static VOID ReleaseWaitInfo(WaitInfo *pInfo)
{
WRAPPER_NO_CONTRACT;
#ifndef DACCESS_COMPILE
ReleaseInfo(pInfo->ExternalEventSafeHandle,
pInfo->handleOwningAD,
pInfo->ExternalCompletionEvent);
#endif
}
static VOID AcquireTimerInfo(TimerInfo *pInfo)
{
}
static VOID ReleaseTimerInfo(TimerInfo *pInfo)
{
WRAPPER_NO_CONTRACT;
#ifndef DACCESS_COMPILE
ReleaseInfo(pInfo->ExternalEventSafeHandle,
pInfo->handleOwningAD,
pInfo->ExternalCompletionEvent);
#endif
}
typedef Holder<WaitInfo *, ThreadpoolMgr::AcquireWaitInfo, ThreadpoolMgr::ReleaseWaitInfo> WaitInfoHolder;
typedef Holder<TimerInfo *, ThreadpoolMgr::AcquireTimerInfo, ThreadpoolMgr::ReleaseTimerInfo> TimerInfoHolder;
typedef struct {
TimerInfo* Timer; // timer to be updated
ULONG DueTime ; // new due time
ULONG Period ; // new period
} TimerUpdateInfo;
// Definitions and data structures to support recycling of high-frequency
// memory blocks. We use a spin-lock to access the list
class RecycledListInfo
{
static const unsigned int MaxCachedEntries = 40;
struct Entry
{
Entry* next;
};
Volatile<LONG> lock; // this is the spin lock
DWORD count; // count of number of elements in the list
Entry* root; // ptr to first element of recycled list
#ifndef _WIN64
DWORD filler; // Pad the structure to a multiple of the 16.
#endif
//--//
public:
RecycledListInfo()
{
LIMITED_METHOD_CONTRACT;
lock = 0;
root = NULL;
count = 0;
}
FORCEINLINE bool CanInsert()
{
LIMITED_METHOD_CONTRACT;
return count < MaxCachedEntries;
}
FORCEINLINE LPVOID Remove()
{
LIMITED_METHOD_CONTRACT;
if(root == NULL) return NULL; // No need for acquiring the lock, there's nothing to remove.
AcquireLock();
Entry* ret = (Entry*)root;
if(ret)
{
root = ret->next;
count -= 1;
}
ReleaseLock();
return ret;
}
FORCEINLINE void Insert( LPVOID mem )
{
LIMITED_METHOD_CONTRACT;
AcquireLock();
Entry* entry = (Entry*)mem;
entry->next = root;
root = entry;
count += 1;
ReleaseLock();
}
private:
FORCEINLINE void AcquireLock()
{
LIMITED_METHOD_CONTRACT;
unsigned int rounds = 0;
DWORD dwSwitchCount = 0;
while(lock != 0 || FastInterlockExchange( &lock, 1 ) != 0)
{
YieldProcessor(); // indicate to the processor that we are spinning
rounds++;
if((rounds % 32) == 0)
{
__SwitchToThread( 0, ++dwSwitchCount );
}
}
}
FORCEINLINE void ReleaseLock()
{
LIMITED_METHOD_CONTRACT;
lock = 0;
}
};
//
// It's critical that we ensure these pointers are allocated by the linker away from
// variables that are modified a lot at runtime.
//
// The use of the CacheGuard is a temporary solution,
// the thread pool has to be refactor away from static variable and
// toward a single global structure, where we can control the locality of variables.
//
class RecycledListsWrapper
{
DWORD CacheGuardPre[64/sizeof(DWORD)];
RecycledListInfo (*pRecycledListPerProcessor)[MEMTYPE_COUNT]; // RecycledListInfo [numProc][MEMTYPE_COUNT]
DWORD CacheGuardPost[64/sizeof(DWORD)];
public:
void Initialize( unsigned int numProcs );
FORCEINLINE bool IsInitialized()
{
LIMITED_METHOD_CONTRACT;
return pRecycledListPerProcessor != NULL;
}
FORCEINLINE RecycledListInfo& GetRecycleMemoryInfo( enum MemType memType )
{
LIMITED_METHOD_CONTRACT;
if (CPUGroupInfo::CanEnableGCCPUGroups() && CPUGroupInfo::CanEnableThreadUseAllCpuGroups())
return pRecycledListPerProcessor[CPUGroupInfo::CalculateCurrentProcessorNumber()][memType];
else
// Turns out GetCurrentProcessorNumber can return a value greater than the number of processors reported by
// GetSystemInfo, if we're running in WOW64 on a machine with >32 processors.
return pRecycledListPerProcessor[GetCurrentProcessorNumber()%NumberOfProcessors][memType];
}
};
#define GATE_THREAD_STATUS_NOT_RUNNING 0 // There is no gate thread
#define GATE_THREAD_STATUS_REQUESTED 1 // There is a gate thread, and someone has asked it to stick around recently
#define GATE_THREAD_STATUS_WAITING_FOR_REQUEST 2 // There is a gate thread, but nobody has asked it to stay. It may die soon
// Private methods
static DWORD __stdcall intermediateThreadProc(PVOID arg);
typedef struct {
LPTHREAD_START_ROUTINE lpThreadFunction;
PVOID lpArg;
} intermediateThreadParam;
static Thread* CreateUnimpersonatedThread(LPTHREAD_START_ROUTINE lpStartAddress, LPVOID lpArgs, BOOL *pIsCLRThread);
static BOOL CreateWorkerThread();
static void EnqueueWorkRequest(WorkRequest* wr);
static WorkRequest* DequeueWorkRequest();
static void ExecuteWorkRequest(bool* foundWork, bool* wasNotRecalled);
static DWORD WINAPI ExecuteHostRequest(PVOID pArg);
#ifndef DACCESS_COMPILE
inline static void AppendWorkRequest(WorkRequest* entry)
{
CONTRACTL
{
NOTHROW;
MODE_ANY;
GC_NOTRIGGER;
}
CONTRACTL_END;
if (WorkRequestTail)
{
_ASSERTE(WorkRequestHead != NULL);
WorkRequestTail->next = entry;
}
else
{
_ASSERTE(WorkRequestHead == NULL);
WorkRequestHead = entry;
}
WorkRequestTail = entry;
_ASSERTE(WorkRequestTail->next == NULL);
}
inline static WorkRequest* RemoveWorkRequest()
{
CONTRACTL
{
NOTHROW;
MODE_ANY;
GC_NOTRIGGER;
}
CONTRACTL_END;
WorkRequest* entry = NULL;
if (WorkRequestHead)
{
entry = WorkRequestHead;
WorkRequestHead = entry->next;
if (WorkRequestHead == NULL)
WorkRequestTail = NULL;
}
return entry;
}
static void EnsureInitialized();
static void InitPlatformVariables();
inline static BOOL IsInitialized()
{
LIMITED_METHOD_CONTRACT;
return Initialization == -1;
}
static void MaybeAddWorkingWorker();
static void NotifyWorkItemCompleted()
{
WRAPPER_NO_CONTRACT;
if (!CLRThreadpoolHosted())
{
Thread::IncrementThreadPoolCompletionCount();
UpdateLastDequeueTime();
}
}
static bool ShouldAdjustMaxWorkersActive()
{
WRAPPER_NO_CONTRACT;
if (CLRThreadpoolHosted())
return false;
DWORD priorTime = PriorCompletedWorkRequestsTime;
MemoryBarrier(); // read fresh value for NextCompletedWorkRequestsTime below
DWORD requiredInterval = NextCompletedWorkRequestsTime - priorTime;
DWORD elapsedInterval = GetTickCount() - priorTime;
if (elapsedInterval >= requiredInterval)
{
ThreadCounter::Counts counts = WorkerCounter.GetCleanCounts();
if (counts.NumActive <= counts.MaxWorking)
return true;
}
return false;
}
static void AdjustMaxWorkersActive();
static bool ShouldWorkerKeepRunning();
static BOOL SuspendProcessing();
static DWORD SafeWait(CLREvent * ev, DWORD sleepTime, BOOL alertable);
static DWORD __stdcall WorkerThreadStart(LPVOID lpArgs);
static BOOL AddWaitRequest(HANDLE waitHandle, WaitInfo* waitInfo);
static ThreadCB* FindWaitThread(); // returns a wait thread that can accomodate another wait request
static BOOL CreateWaitThread();
static void __stdcall InsertNewWaitForSelf(WaitInfo* pArg);
static int FindWaitIndex(const ThreadCB* threadCB, const HANDLE waitHandle);
static DWORD MinimumRemainingWait(LIST_ENTRY* waitInfo, unsigned int numWaits);
static void ProcessWaitCompletion( WaitInfo* waitInfo,
unsigned index, // array index
BOOL waitTimedOut);
static DWORD __stdcall WaitThreadStart(LPVOID lpArgs);
static DWORD __stdcall AsyncCallbackCompletion(PVOID pArgs);
static void QueueTimerInfoForRelease(TimerInfo *pTimerInfo);
static DWORD __stdcall QUWIPostCompletion(PVOID pArgs);
static void DeactivateWait(WaitInfo* waitInfo);
static void DeactivateNthWait(WaitInfo* waitInfo, DWORD index);
static void DeleteWait(WaitInfo* waitInfo);
inline static void ShiftWaitArray( ThreadCB* threadCB,
ULONG SrcIndex,
ULONG DestIndex,
ULONG count)
{
LIMITED_METHOD_CONTRACT;
memmove(&threadCB->waitHandle[DestIndex],
&threadCB->waitHandle[SrcIndex],
count * sizeof(HANDLE));
memmove(&threadCB->waitPointer[DestIndex],
&threadCB->waitPointer[SrcIndex],
count * sizeof(LIST_ENTRY));
}
static void __stdcall DeregisterWait(WaitInfo* pArgs);
#ifndef FEATURE_PAL
// holds the aggregate of system cpu usage of all processors
typedef struct _PROCESS_CPU_INFORMATION
{
LARGE_INTEGER idleTime;
LARGE_INTEGER kernelTime;
LARGE_INTEGER userTime;
DWORD_PTR affinityMask;
int numberOfProcessors;
SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION* usageBuffer;
int usageBufferSize;
} PROCESS_CPU_INFORMATION;
static int GetCPUBusyTime_NT(PROCESS_CPU_INFORMATION* pOldInfo);
static BOOL CreateCompletionPortThread(LPVOID lpArgs);
static DWORD __stdcall CompletionPortThreadStart(LPVOID lpArgs);
public:
inline static bool HaveNativeWork()
{
LIMITED_METHOD_CONTRACT;
return WorkRequestHead != NULL;
}
static void GrowCompletionPortThreadpoolIfNeeded();
static BOOL ShouldGrowCompletionPortThreadpool(ThreadCounter::Counts counts);
#else
static int GetCPUBusyTime_NT(PAL_IOCP_CPU_INFORMATION* pOldInfo);
#endif // !FEATURE_PAL
private:
static BOOL IsIoPending();
static BOOL CreateGateThread();
static void EnsureGateThreadRunning();
static bool ShouldGateThreadKeepRunning();
static DWORD __stdcall GateThreadStart(LPVOID lpArgs);
static BOOL SufficientDelaySinceLastSample(unsigned int LastThreadCreationTime,
unsigned NumThreads, // total number of threads of that type (worker or CP)
double throttleRate=0.0 // the delay is increased by this percentage for each extra thread
);
static BOOL SufficientDelaySinceLastDequeue();
static LPVOID GetRecycledMemory(enum MemType memType);
static DWORD __stdcall TimerThreadStart(LPVOID args);
static void TimerThreadFire(); // helper method used by TimerThreadStart
static void __stdcall InsertNewTimer(TimerInfo* pArg);
static DWORD FireTimers();
static DWORD __stdcall AsyncTimerCallbackCompletion(PVOID pArgs);
static void DeactivateTimer(TimerInfo* timerInfo);
static DWORD __stdcall AsyncDeleteTimer(PVOID pArgs);
static void DeleteTimer(TimerInfo* timerInfo);
static void __stdcall UpdateTimer(TimerUpdateInfo* pArgs);
static void __stdcall DeregisterTimer(TimerInfo* pArgs);
inline static DWORD QueueDeregisterWait(HANDLE waitThread, WaitInfo* waitInfo)
{
CONTRACTL
{
NOTHROW;
MODE_ANY;
GC_NOTRIGGER;
}
CONTRACTL_END;
DWORD result = QueueUserAPC(reinterpret_cast<PAPCFUNC>(DeregisterWait), waitThread, reinterpret_cast<ULONG_PTR>(waitInfo));
SetWaitThreadAPCPending();
return result;
}
inline static void SetWaitThreadAPCPending() {IsApcPendingOnWaitThread = TRUE;}
inline static void ResetWaitThreadAPCPending() {IsApcPendingOnWaitThread = FALSE;}
inline static BOOL IsWaitThreadAPCPending() {return IsApcPendingOnWaitThread;}
#ifdef _DEBUG
inline static DWORD GetTickCount()
{
LIMITED_METHOD_CONTRACT;
return ::GetTickCount() + TickCountAdjustment;
}
#endif
#endif // #ifndef DACCESS_COMPILE
// Private variables
static LONG Initialization; // indicator of whether the threadpool is initialized.
SVAL_DECL(LONG,MinLimitTotalWorkerThreads); // same as MinLimitTotalCPThreads
SVAL_DECL(LONG,MaxLimitTotalWorkerThreads); // same as MaxLimitTotalCPThreads
DECLSPEC_ALIGN(64) static unsigned int LastDequeueTime; // used to determine if work items are getting thread starved
static HillClimbing HillClimbingInstance;
DECLSPEC_ALIGN(64) static LONG PriorCompletedWorkRequests;
static DWORD PriorCompletedWorkRequestsTime;
static DWORD NextCompletedWorkRequestsTime;
static LARGE_INTEGER CurrentSampleStartTime;
static int ThreadAdjustmentInterval;
SPTR_DECL(WorkRequest,WorkRequestHead); // Head of work request queue
SPTR_DECL(WorkRequest,WorkRequestTail); // Head of work request queue
static unsigned int LastCPThreadCreation; // last time a completion port thread was created
static unsigned int NumberOfProcessors; // = NumberOfWorkerThreads - no. of blocked threads
static BOOL IsApcPendingOnWaitThread; // Indicates if an APC is pending on the wait thread
// This needs to be non-hosted, because worker threads can run prior to EE startup.
static DangerousNonHostedSpinLock ThreadAdjustmentLock;
public:
static CrstStatic WorkerCriticalSection;
private:
static const DWORD WorkerTimeout = 20 * 1000;
static const DWORD WorkerTimeoutAppX = 5 * 1000; // shorter timeout to allow threads to exit prior to app suspension
DECLSPEC_ALIGN(64) SVAL_DECL(ThreadCounter,WorkerCounter);
//
// WorkerSemaphore is an UnfairSemaphore because:
// 1) Threads enter and exit this semaphore very frequently, and thus benefit greatly from the spinning done by UnfairSemaphore
// 2) There is no functional reason why any particular thread should be preferred when waking workers. This only impacts performance,
// and un-fairness helps performance in this case.
//
static UnfairSemaphore* WorkerSemaphore;
//
// RetiredWorkerSemaphore is a regular CLRSemaphore, not an UnfairSemaphore, because if a thread waits on this semaphore is it almost certainly
// NOT going to be released soon, so the spinning done in UnfairSemaphore only burns valuable CPU time. However, if UnfairSemaphore is ever
// implemented in terms of a Win32 IO Completion Port, we should reconsider this. The IOCP's LIFO unblocking behavior could help keep working set
// down, by constantly re-using the same small set of retired workers rather than round-robining between all of them as CLRSemaphore will do.
// If we go that route, we should add a "no-spin" option to UnfairSemaphore.Wait to avoid wasting CPU.
//
static CLRSemaphore* RetiredWorkerSemaphore;
static CLREvent * RetiredCPWakeupEvent;
static CrstStatic WaitThreadsCriticalSection;
static LIST_ENTRY WaitThreadsHead; // queue of wait threads, each thread can handle upto 64 waits
static TimerInfo *TimerInfosToBeRecycled; // list of delegate infos associated with deleted timers
static CrstStatic TimerQueueCriticalSection; // critical section to synchronize timer queue access
SVAL_DECL(LIST_ENTRY,TimerQueue); // queue of timers
static HANDLE TimerThread; // Currently we only have one timer thread
static Thread* pTimerThread;
DECLSPEC_ALIGN(64) static DWORD LastTickCount; // the count just before timer thread goes to sleep
static BOOL InitCompletionPortThreadpool; // flag indicating whether completion port threadpool has been initialized
static HANDLE GlobalCompletionPort; // used for binding io completions on file handles
public:
SVAL_DECL(ThreadCounter,CPThreadCounter);
private:
SVAL_DECL(LONG,MaxLimitTotalCPThreads); // = MaxLimitCPThreadsPerCPU * number of CPUS
SVAL_DECL(LONG,MinLimitTotalCPThreads);
SVAL_DECL(LONG,MaxFreeCPThreads); // = MaxFreeCPThreadsPerCPU * Number of CPUS
DECLSPEC_ALIGN(64) static LONG GateThreadStatus; // See GateThreadStatus enumeration
static Volatile<LONG> NumCPInfrastructureThreads; // number of threads currently busy handling draining cycle
SVAL_DECL(LONG,cpuUtilization);
static LONG cpuUtilizationAverage;
DECLSPEC_ALIGN(64) static RecycledListsWrapper RecycledLists;
#ifdef _DEBUG
static DWORD TickCountAdjustment; // add this value to value returned by GetTickCount
#endif
DECLSPEC_ALIGN(64) static int offset_counter;
static const int offset_multiplier = 128;
};
#endif // _WIN32THREADPOOL_H
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