1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
/*=========================================================================
Program: Visualization Toolkit
Module: vtkSMPToolsImpl.cxx
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.
=========================================================================*/
#include "SMP/Common/vtkSMPToolsImpl.h"
#include "SMP/STDThread/vtkSMPToolsImpl.txx"
#include <cstdlib> // For std::getenv()
#include <stack> // For std::stack
#include <thread> // For std::thread::hardware_concurrency()
namespace vtk
{
namespace detail
{
namespace smp
{
VTK_ABI_NAMESPACE_BEGIN
static int specifiedNumThreads = 0;
static std::stack<std::thread::id> threadIdStack;
static std::mutex threadIdStackLock;
//------------------------------------------------------------------------------
template <>
void vtkSMPToolsImpl<BackendType::STDThread>::Initialize(int numThreads)
{
const int maxThreads = std::thread::hardware_concurrency();
if (numThreads == 0)
{
const char* vtkSmpNumThreads = std::getenv("VTK_SMP_MAX_THREADS");
if (vtkSmpNumThreads)
{
numThreads = std::atoi(vtkSmpNumThreads);
}
else
{
specifiedNumThreads = 0;
}
}
if (numThreads > 0)
{
numThreads = std::min(numThreads, maxThreads);
specifiedNumThreads = numThreads;
}
}
//------------------------------------------------------------------------------
int GetNumberOfThreadsSTDThread()
{
return specifiedNumThreads ? specifiedNumThreads : std::thread::hardware_concurrency();
}
//------------------------------------------------------------------------------
void PushThreadId(std::thread::id id)
{
threadIdStackLock.lock();
threadIdStack.emplace(id);
threadIdStackLock.unlock();
}
//------------------------------------------------------------------------------
void PopThreadId()
{
threadIdStackLock.lock();
threadIdStack.pop();
threadIdStackLock.unlock();
}
//------------------------------------------------------------------------------
bool GetSingleThreadSTDThread()
{
return threadIdStack.top() == std::this_thread::get_id();
}
//------------------------------------------------------------------------------
template <>
int vtkSMPToolsImpl<BackendType::STDThread>::GetEstimatedNumberOfThreads()
{
return GetNumberOfThreadsSTDThread();
}
//------------------------------------------------------------------------------
template <>
bool vtkSMPToolsImpl<BackendType::STDThread>::GetSingleThread()
{
return GetSingleThreadSTDThread();
}
VTK_ABI_NAMESPACE_END
} // namespace smp
} // namespace detail
} // namespace vtk
|
