1#pragma once
2
3#include <atomic>
4#include <cstddef>
5#include <exception>
6
7#ifdef _OPENMP
8#define INTRA_OP_PARALLEL
9
10#include <omp.h>
11#endif
12
13namespace at {
14
15#ifdef _OPENMP
16namespace internal {
17template <typename F>
18inline void invoke_parallel(
19 int64_t begin,
20 int64_t end,
21 int64_t grain_size,
22 const F& f) {
23 std::atomic_flag err_flag = ATOMIC_FLAG_INIT;
24 std::exception_ptr eptr;
25
26#pragma omp parallel
27 {
28 // choose number of tasks based on grain size and number of threads
29 // can't use num_threads clause due to bugs in GOMP's thread pool (See
30 // #32008)
31 int64_t num_threads = omp_get_num_threads();
32 if (grain_size > 0) {
33 num_threads = std::min(num_threads, divup((end - begin), grain_size));
34 }
35
36 int64_t tid = omp_get_thread_num();
37 int64_t chunk_size = divup((end - begin), num_threads);
38 int64_t begin_tid = begin + tid * chunk_size;
39 if (begin_tid < end) {
40 try {
41 internal::ThreadIdGuard tid_guard(tid);
42 f(begin_tid, std::min(end, chunk_size + begin_tid));
43 } catch (...) {
44 if (!err_flag.test_and_set()) {
45 eptr = std::current_exception();
46 }
47 }
48 }
49 }
50 if (eptr) {
51 std::rethrow_exception(eptr);
52 }
53}
54} // namespace internal
55#endif // _OPENMP
56
57} // namespace at
58