IDXTaskManager Interface

CLSID_DXTaskManager

{4CB26C03-FF93-11D0-817E-0000F87557DB}

IID_IDXTaskManager

{254DBBC1-F922-11D0-883A-3C8B00C10000}

The IDXTaskManager interface enables you to configure the task manager to specify the thread pool size and the thread concurrency limit.

Remarks

The task manager is a generic service used to schedule and execute caller-defined tasks. It automatically breaks a transform task into threads and manages their completion, which improves the efficiency of the transform.

The default thread pool size is two threads per processor, and the default concurrency limit is one thread per processor. The default implementation uses input/output completion ports on Microsoft Windows NT to optimize processor utilization.
 

Methods in VTable order

IUnknown Methods

Description

QueryInterface

Returns pointers to supported interfaces.

AddRef

Increments reference count.

Release

Decrements reference count.

IDXTaskManager Members

Description

QueryNumProcessors

Retrieves the number of processors installed in the system.

SetThreadPoolSize

Specifies the number of threads to create and make available to execute tasks.

GetThreadPoolSize

Retrieves the number of threads in the thread pool.

SetConcurrencyLimit

Defines the number of threads that can execute from a thread pool at a given time.

GetConcurrencyLimit

Retrieves the number of threads allowed to execute on a single processor at a given time.

ScheduleTasks

Defines a set of tasks to execute.

TerminateTasks

Terminates a set of tasks previously scheduled by the task manager.

TerminateRequest

Terminates a task based on its request identifier (ID) value that was used when the task was scheduled.

QueryNumProcessors

FUNCTION IDXTaskManager_QueryNumProcessors ( _
  BYVAL pthis AS DWORD PTR _
, BYREF pulNumProc AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[3] USING IDXTaskManager_QueryNumProcessors (pthis, pulNumProc) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION
 

SetThreadPoolSize

FUNCTION IDXTaskManager_SetThreadPoolSize ( _
  BYVAL pthis AS DWORD PTR _
, BYVAL ulNumThreads AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[4] USING IDXTaskManager_SetThreadPoolSize (pthis, ulNumThreads) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION
 

GetThreadPoolSize

FUNCTION IDXTaskManager_GetThreadPoolSize ( _
  BYVAL pthis AS DWORD PTR _
, BYREF pulNumThreads AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[5] USING IDXTaskManager_GetThreadPoolSize (pthis, pulNumThreads) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION
 

SetConcurrencyLimit

FUNCTION IDXTaskManager_SetConcurrencyLimit ( _
  BYVAL pthis AS DWORD PTR _
, BYVAL ulNumThreads AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[6] USING IDXTaskManager_SetConcurrencyLimit (pthis, ulNumThreads) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION
 

GetConcurrencyLimit

FUNCTION IDXTaskManager_GetConcurrencyLimit ( _
  BYVAL pthis AS DWORD PTR _
, BYREF pulNumThreads AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[7] USING IDXTaskManager_GetConcurrencyLimit (pthis, pulNumThreads) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION
 

ScheduleTasks

FUNCTION IDXTaskManager_ScheduleTasks ( _
  BYVAL pthis AS DWORD PTR _
, BYREF TaskInfo AS DXTMTASKINFO _
, BYVAL Events AS DWORD _
, BYREF TaskIDs AS DWORD _
, BYVAL ulNumTasks AS DWORD _
, BYVAL ulWaitPeriod AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[8] USING IDXTaskManager_ScheduleTasks (pthis, TaskInfo, Events, TaskIDs, ulNumTasks, ulWaitPeriod) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION
 

TerminateTasks

FUNCTION IDXTaskManager_TerminateTasks ( _
  BYVAL pthis AS DWORD PTR _
, BYVAL TaskIDs AS DWORD PTR _
, BYVAL ulCount AS DWORD _
, BYVAL ulTimeOut AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[9] USING IDXTaskManager_TerminateTasks (pthis, TaskIDs, ulCount, ulTimeOut) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION
 

TerminateRequest

FUNCTION IDXTaskManager_TerminateRequest ( _
  BYVAL pthis AS DWORD PTR _
, BYREF RequestID AS GUID _
, BYVAL ulTimeOut AS DWORD _
  ) AS LONG

  LOCAL HRESULT AS LONG
  CALL DWORD @@pthis[10] USING IDXTaskManager_TerminateRequest (pthis, RequestID, ulTimeOut) TO HRESULT
  FUNCTION = HRESULT

END FUNCTION