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