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/*=========================================================================
Program: Visualization Toolkit
Module: vtkMultiThreader.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/**
* @class vtkMultiThreader
* @brief A class for performing multithreaded execution
*
* vtkMultithreader is a class that provides support for multithreaded
* execution using pthreads on POSIX systems, or Win32 threads on
* Windows. This class can be used to execute a single
* method on multiple threads, or to specify a method per thread.
*/
#ifndef vtkMultiThreader_h
#define vtkMultiThreader_h
#include "vtkCommonCoreModule.h" // For export macro
#include "vtkObject.h"
#include <mutex> // For std::mutex
#if defined(VTK_USE_PTHREADS)
#include <pthread.h> // Needed for PTHREAD implementation of mutex
#include <sys/types.h> // Needed for unix implementation of pthreads
#include <unistd.h> // Needed for unix implementation of pthreads
#endif
// If VTK_USE_PTHREADS is defined, then pthread_create() will be
// used to create multiple threads
// Defined in vtkSystemIncludes.h:
// VTK_MAX_THREADS
// If VTK_USE_PTHREADS is defined, then the multithreaded
// function is of type void *, and returns nullptr
// Otherwise the type is void which is correct for WIN32
// Defined in vtkSystemIncludes.h:
// VTK_THREAD_RETURN_VALUE
// VTK_THREAD_RETURN_TYPE
#ifdef VTK_USE_PTHREADS
typedef void* (*vtkThreadFunctionType)(void*);
typedef pthread_t vtkThreadProcessIDType;
// #define VTK_THREAD_RETURN_VALUE nullptr
// #define VTK_THREAD_RETURN_TYPE void *
typedef pthread_t vtkMultiThreaderIDType;
#endif
#ifdef VTK_USE_WIN32_THREADS
typedef vtkWindowsLPTHREAD_START_ROUTINE vtkThreadFunctionType;
typedef vtkWindowsHANDLE vtkThreadProcessIDType;
// #define VTK_THREAD_RETURN_VALUE 0
// #define VTK_THREAD_RETURN_TYPE DWORD __stdcall
typedef vtkWindowsDWORD vtkMultiThreaderIDType;
#endif
#if !defined(VTK_USE_PTHREADS) && !defined(VTK_USE_WIN32_THREADS)
typedef void (*vtkThreadFunctionType)(void*);
typedef int vtkThreadProcessIDType;
// #define VTK_THREAD_RETURN_VALUE
// #define VTK_THREAD_RETURN_TYPE void
typedef int vtkMultiThreaderIDType;
#endif
class VTKCOMMONCORE_EXPORT vtkMultiThreader : public vtkObject
{
public:
static vtkMultiThreader* New();
vtkTypeMacro(vtkMultiThreader, vtkObject);
void PrintSelf(ostream& os, vtkIndent indent) override;
/**
* This is the structure that is passed to the thread that is
* created from the SingleMethodExecute, MultipleMethodExecute or
* the SpawnThread method. It is passed in as a void *, and it is
* up to the method to cast correctly and extract the information.
* The ThreadID is a number between 0 and NumberOfThreads-1 that indicates
* the id of this thread. The NumberOfThreads is this->NumberOfThreads for
* threads created from SingleMethodExecute or MultipleMethodExecute,
* and it is 1 for threads created from SpawnThread.
* The UserData is the (void *)arg passed into the SetSingleMethod,
* SetMultipleMethod, or SpawnThread method.
*/
class ThreadInfo
{
public:
int ThreadID;
int NumberOfThreads;
int* ActiveFlag;
std::mutex* ActiveFlagLock;
void* UserData;
};
//@{
/**
* Get/Set the number of threads to create. It will be clamped to the range
* 1 - VTK_MAX_THREADS, so the caller of this method should check that the
* requested number of threads was accepted.
*/
vtkSetClampMacro(NumberOfThreads, int, 1, VTK_MAX_THREADS);
virtual int GetNumberOfThreads();
//@}
//@{
/**
* Set/Get the maximum number of threads to use when multithreading.
* This limits and overrides any other settings for multithreading.
* A value of zero indicates no limit.
*/
static void SetGlobalMaximumNumberOfThreads(int val);
static int GetGlobalMaximumNumberOfThreads();
//@}
//@{
/**
* Set/Get the value which is used to initialize the NumberOfThreads
* in the constructor. Initially this default is set to the number of
* processors or VTK_MAX_THREADS (which ever is less).
*/
static void SetGlobalDefaultNumberOfThreads(int val);
static int GetGlobalDefaultNumberOfThreads();
//@}
// These methods are excluded from wrapping 1) because the
// wrapper gives up on them and 2) because they really shouldn't be
// called from a script anyway.
/**
* Execute the SingleMethod (as define by SetSingleMethod) using
* this->NumberOfThreads threads.
*/
void SingleMethodExecute();
/**
* Execute the MultipleMethods (as define by calling SetMultipleMethod
* for each of the required this->NumberOfThreads methods) using
* this->NumberOfThreads threads.
*/
void MultipleMethodExecute();
/**
* Set the SingleMethod to f() and the UserData field of the
* ThreadInfo that is passed to it will be data.
* This method (and all the methods passed to SetMultipleMethod)
* must be of type vtkThreadFunctionType and must take a single argument of
* type void *.
*/
void SetSingleMethod(vtkThreadFunctionType, void* data);
/**
* Set the MultipleMethod at the given index to f() and the UserData
* field of the ThreadInfo that is passed to it will be data.
*/
void SetMultipleMethod(int index, vtkThreadFunctionType, void* data);
/**
* Create a new thread for the given function. Return a thread id
* which is a number between 0 and VTK_MAX_THREADS - 1. This id should
* be used to kill the thread at a later time.
*/
int SpawnThread(vtkThreadFunctionType, void* data);
/**
* Terminate the thread that was created with a SpawnThreadExecute()
*/
void TerminateThread(int thread_id);
/**
* Determine if a thread is still active
*/
vtkTypeBool IsThreadActive(int threadID);
/**
* Get the thread identifier of the calling thread.
*/
static vtkMultiThreaderIDType GetCurrentThreadID();
/**
* Check whether two thread identifiers refer to the same thread.
*/
static vtkTypeBool ThreadsEqual(vtkMultiThreaderIDType t1, vtkMultiThreaderIDType t2);
protected:
vtkMultiThreader();
~vtkMultiThreader() override;
// The number of threads to use
int NumberOfThreads;
// An array of thread info containing a thread id
// (0, 1, 2, .. VTK_MAX_THREADS-1), the thread count, and a pointer
// to void so that user data can be passed to each thread
ThreadInfo ThreadInfoArray[VTK_MAX_THREADS];
// The methods
vtkThreadFunctionType SingleMethod;
vtkThreadFunctionType MultipleMethod[VTK_MAX_THREADS];
// Storage of MutexFunctions and ints used to control spawned
// threads and the spawned thread ids
int SpawnedThreadActiveFlag[VTK_MAX_THREADS];
std::mutex* SpawnedThreadActiveFlagLock[VTK_MAX_THREADS];
vtkThreadProcessIDType SpawnedThreadProcessID[VTK_MAX_THREADS];
ThreadInfo SpawnedThreadInfoArray[VTK_MAX_THREADS];
// Internal storage of the data
void* SingleData;
void* MultipleData[VTK_MAX_THREADS];
private:
vtkMultiThreader(const vtkMultiThreader&) = delete;
void operator=(const vtkMultiThreader&) = delete;
};
using ThreadInfoStruct = vtkMultiThreader::ThreadInfo;
#endif