Compute Library
 21.02
OMPScheduler.cpp
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25 
27 #include "arm_compute/core/Error.h"
29 #include "arm_compute/core/Utils.h"
30 #include "src/runtime/CPUUtils.h"
31 #include <omp.h>
32 
33 namespace arm_compute
34 {
36  : _num_threads(omp_get_max_threads())
37 {
38 }
39 
40 unsigned int OMPScheduler::num_threads() const
41 {
42  return _num_threads;
43 }
44 
46 {
47  const unsigned int num_cores = omp_get_max_threads();
48  _num_threads = (num_threads == 0) ? num_cores : num_threads;
49 }
50 
51 void OMPScheduler::schedule(ICPPKernel *kernel, const Hints &hints)
52 {
53  ITensorPack tensors;
54  schedule_common(kernel, hints, kernel->window(), tensors);
55 }
56 
57 void OMPScheduler::schedule_op(ICPPKernel *kernel, const Hints &hints, const Window &window, ITensorPack &tensors)
58 {
59  ARM_COMPUTE_ERROR_ON_MSG(!kernel, "The child class didn't set the kernel");
61  "Dynamic scheduling is not supported in OMPScheduler");
62 
63  const Window &max_window = window;
64  const unsigned int num_iterations = max_window.num_iterations(hints.split_dimension());
65  const unsigned int num_threads = std::min(num_iterations, _num_threads);
66 
67  if(!kernel->is_parallelisable() || num_threads == 1)
68  {
70  info.cpu_info = &_cpu_info;
71  kernel->run_op(tensors, max_window, info);
72  }
73  else
74  {
75  const unsigned int num_windows = num_threads;
76  std::vector<IScheduler::Workload> workloads(num_windows);
77  for(unsigned int t = 0; t < num_windows; t++)
78  {
79  //Capture 't' by copy, all the other variables by reference:
80  workloads[t] = [t, &hints, &max_window, &num_windows, &kernel, &tensors](const ThreadInfo & info)
81  {
82  Window win = max_window.split_window(hints.split_dimension(), t, num_windows);
83  win.validate();
84  kernel->run_op(tensors, win, info);
85  };
86  }
87  run_workloads(workloads);
88  }
89 }
90 #ifndef DOXYGEN_SKIP_THIS
91 void OMPScheduler::run_workloads(std::vector<arm_compute::IScheduler::Workload> &workloads)
92 {
93  const unsigned int num_threads = std::min(_num_threads, static_cast<unsigned int>(workloads.size()));
94  if(num_threads < 1)
95  {
96  return;
97  }
98 
100  info.cpu_info = &_cpu_info;
101  info.num_threads = num_threads;
102  #pragma omp parallel firstprivate(info) num_threads(num_threads)
103  {
104  const int tid = omp_get_thread_num();
105  info.thread_id = tid;
106  workloads[tid](info);
107  }
108 }
109 #endif /* DOXYGEN_SKIP_THIS */
110 } // namespace arm_compute
const Window & window() const
The maximum window the kernel can be executed on.
Definition: IKernel.cpp:28
void schedule_op(ICPPKernel *kernel, const Hints &hints, const Window &window, ITensorPack &tensors) override
Multithread the execution of the passed kernel if possible.
OMPScheduler()
Constructor.
Common interface for all kernels implemented in C++.
Definition: ICPPKernel.h:38
void set_num_threads(unsigned int num_threads) override
Sets the number of threads the scheduler will use to run the kernels.
Window split_window(size_t dimension, size_t id, size_t total) const
Split a window into a set of sub windows along a given dimension.
Definition: Window.inl:189
virtual void run_op(ITensorPack &tensors, const Window &window, const ThreadInfo &info)
Execute the kernel on the passed window.
Definition: ICPPKernel.h:86
void validate() const
Will validate all the window&#39;s dimensions&#39; values when asserts are enabled.
Definition: Window.inl:173
constexpr size_t num_iterations(size_t dimension) const
Return the number of iterations needed to iterate through a given dimension.
Definition: Window.inl:182
OpenMP scheduler (Alternative to the CPPScheduler).
Copyright (c) 2017-2021 Arm Limited.
Split the workload dynamically using a bucket system.
StrategyHint strategy() const
Return the prefered strategy to use to split workload.
Definition: IScheduler.h:116
virtual bool is_parallelisable() const
Indicates whether or not the kernel is parallelisable.
Definition: IKernel.cpp:41
#define ARM_COMPUTE_ERROR_ON_MSG(cond, msg)
Definition: Error.h:456
void schedule(ICPPKernel *kernel, const Hints &hints) override
Multithread the execution of the passed kernel if possible.
ScaleKernelInfo info(interpolation_policy, default_border_mode, PixelValue(), sampling_policy, false)
Information about executing thread and CPU.
Definition: CPPTypes.h:235
unsigned int num_threads() const override
Returns the number of threads that the OMPScheduler has in its pool.
Tensor packing service.
Definition: ITensorPack.h:37
unsigned int split_dimension() const
Return the prefered split dimension.
Definition: IScheduler.h:96
const CPUInfo * cpu_info
Definition: CPPTypes.h:239
Describe a multidimensional execution window.
Definition: Window.h:39