diff options
| -rw-r--r-- | gdbsupport/parallel-for.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/gdbsupport/parallel-for.h b/gdbsupport/parallel-for.h index cfe8a6e..bf40f12 100644 --- a/gdbsupport/parallel-for.h +++ b/gdbsupport/parallel-for.h @@ -147,6 +147,8 @@ parallel_for_each (unsigned n, RandomIt first, RandomIt last, size_t n_threads = n_worker_threads; size_t n_elements = last - first; size_t elts_per_thread = 0; + size_t elts_left_over = 0; + if (n_threads > 1) { /* Require that there should be at least N elements in a @@ -155,6 +157,8 @@ parallel_for_each (unsigned n, RandomIt first, RandomIt last, if (n_elements / n_threads < n) n_threads = std::max (n_elements / n, (size_t) 1); elts_per_thread = n_elements / n_threads; + elts_left_over = n_elements % n_threads; + /* n_elements == n_threads * elts_per_thread + elts_left_over. */ } size_t count = n_threads == 0 ? 0 : n_threads - 1; @@ -170,6 +174,10 @@ parallel_for_each (unsigned n, RandomIt first, RandomIt last, for (int i = 0; i < count; ++i) { RandomIt end = first + elts_per_thread; + if (i < elts_left_over) + /* Distribute the leftovers over the worker threads, to avoid having + to handle all of them in a single thread. */ + end++; if (parallel_for_each_debug) debug_printf (_("Parallel for: elements on worker thread %i\t: %zu\n"), i, (size_t)(end - first)); |