144 lines
5 KiB
C
144 lines
5 KiB
C
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/*++
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Copyright (C) 2001 Microsoft Corporation
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Module Name:
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THRPOOL.H
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Abstract:
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General purpose thread pool.
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History:
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raymcc 25-Feb-99 Created
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--*/
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#ifndef _THRPOOL_H_
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#define _THRPOOL_H_
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class POLARITY CThreadPool
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{
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// User-defined control parms.
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// ===========================
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DWORD m_dwMsMaxIdle; // Max idle milliseconds before letting thread terminate
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LONG m_lMaxThreads; // Max threads in pool, -1 = no limit.
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LONG m_lIdleThreadLimit; // No more than this number of idle threads
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// Thread status info. These may become out-of-date as soon as they
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// are read, but they are statistically useful.
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// =================================================================
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LONG m_lIdleThreads; // How many threads available
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LONG m_lTotalThreads; // How many threads created
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// Other stuff.
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// ============
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HANDLE m_hReleaseThread; // Signaled to release a blocked thread
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HANDLE m_hBeginRendezvous; // Signaled to indicate a rendezvous
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HANDLE m_hParmXfer; // Signaled to begin interthread transfer of parms
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HANDLE m_hEndRendezvous; // Signaled when parameter transfer is completed
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CRITICAL_SECTION m_cs_dispatch; // Protects dispatcher rendezvous
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CRITICAL_SECTION m_cs_pool; // Protects thread pool rendezvous
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bool m_bShutdown;
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bool m_bPendingRequest; // Used to signal that a parm transfer
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// is taking place via the two Xfer members
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// following this.
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// These are used for interthread parameter transfers.
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// ====================================================
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LPVOID m_pXferUserParms; // Used to copy user-supplied thread parms
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LPTHREAD_START_ROUTINE m_pXferUserProc; // Used to copy the user-supplied
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// thread entry point
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LPDWORD m_pXferReturnCode; // Receives user's return code
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LPDWORD m_pXferElapsedTime; // Receives elapsed dispatch time
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HANDLE m_hXferThreadCompleted; // Signaled when thread is done
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// Internal functions.
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// ===================
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bool CreateNewThread();
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static DWORD WINAPI _ThreadEntry(LPVOID pArg);
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void Pool();
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public:
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enum { NoError, ExceededPool, ThreadCreationFailure, ShutdownInProgress, Failed, TimedOut };
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CThreadPool(
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DWORD dwMsMaxIdleBeforeDie = 5000, // 5 sec
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LONG lIdleThreadLimit = 8, // No more than this number of idle threads, -1=no limit
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LONG lMaxThreads = -1 // No limit
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);
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~CThreadPool();
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void IncrementMaxThreads() { InterlockedIncrement(&m_lMaxThreads); }
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void DecrementMaxThreads() { InterlockedDecrement(&m_lMaxThreads); }
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LONG GetCurrentMaxThreads() { return m_lMaxThreads; }
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bool Shutdown(DWORD dwMaxWait = 5000);
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// Stops dispatching and lets thread pool return to
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// zero. New requests via DispatchThread() will be denied
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// with a <Shutdown> error code.
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// If this returns while there still threads due to timeout,
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// <false> is returned.
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bool Restart();
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// Allows thread pool to start again.
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// All of these can become out of date before the call even returns!
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// They are primarily for load analysis and don't have to be exact.
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// =================================================================
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LONG GetTotalThreadCount() { return m_lTotalThreads; }
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LONG GetIdleThreadCount() { return m_lIdleThreads; }
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// Dispatches a thread to the user's entry point.
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// ==============================================
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int DispatchThread(
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IN DWORD dwMaxPreferredWait,
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IN DWORD dwMaxWaitBeforeFail,
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IN LPTHREAD_START_ROUTINE pEntry,
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IN LPVOID pArg = 0,
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IN DWORD *pdwReturnCode = 0,
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IN DWORD *pdwElapsedTime = 0,
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IN HANDLE hThreadCompleted = 0
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);
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/*
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dwMaxPreferredWait --
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How long to wait while attempting to reuse a thread which
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has just become idle. Typically, no more than 250 msec.
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Once this expires, if no threads are available, one will
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be created, if the max thread limit hasn't been reached.
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If it has, then dwMaxWaitBeforeFail kicks in.
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dwMaxWaitBeforeFail --
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The maximum wait time to acquire or create a thread. If
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a thread cannot be dispatched within this time, ExceededPool
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is returned.
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pEntry --
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The user's entry point.
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pdwReturnCode --
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If not NULL, receives the thread return code.
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pdwElapsedTime --
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If not NULL, receives the elapsed running time of the dispatch.
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hThreadCompleted
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If not NULL, a user event handle to be signaled when thread is done
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Return value --
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One of the enum error codes
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*/
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};
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#endif
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