gdb/unittests/parallel-for-selftests.c

   1 /* Self tests for parallel_for_each
   2
   3    Copyright (C) 2021-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 /* This file is divided in two parts:
  21    - FOR_EACH-undefined, and
  22    - FOR_EACH-defined.
  23    The former includes the latter, more than once, with different values for
  24    FOR_EACH.  The FOR_EACH-defined part reads like a regular function.  */
  25 #ifndef FOR_EACH
  26
  27 #include "gdbsupport/selftest.h"
  28 #include "gdbsupport/parallel-for.h"
  29
  30 #if CXX_STD_THREAD
  31
  32 #include "gdbsupport/thread-pool.h"
  33
  34 namespace selftests {
  35 namespace parallel_for {
  36
  37 struct save_restore_n_threads
  38 {
  39   save_restore_n_threads ()
  40     : n_threads (gdb::thread_pool::g_thread_pool->thread_count ())
  41   {
  42   }
  43
  44   ~save_restore_n_threads ()
  45   {
  46     gdb::thread_pool::g_thread_pool->set_thread_count (n_threads);
  47   }
  48
  49   int n_threads;
  50 };
  51
  52 /* Define test_par using TEST in the FOR_EACH-defined part.  */
  53 #define TEST test_par
  54 #define FOR_EACH gdb::parallel_for_each
  55 #include "parallel-for-selftests.c"
  56 #undef FOR_EACH
  57 #undef TEST
  58
  59 /* Define test_seq using TEST in the FOR_EACH-defined part.  */
  60 #define TEST test_seq
  61 #define FOR_EACH gdb::sequential_for_each
  62 #include "parallel-for-selftests.c"
  63 #undef FOR_EACH
  64 #undef TEST
  65
  66 static void
  67 test (int n_threads)
  68 {
  69   test_par (n_threads);
  70   test_seq (n_threads);
  71 }
  72
  73 static void
  74 test_n_threads ()
  75 {
  76   test (0);
  77   test (1);
  78   test (3);
  79 }
  80
  81 }
  82 }
  83
  84 #endif /* CXX_STD_THREAD */
  85
  86 void _initialize_parallel_for_selftests ();
  87 void
  88 _initialize_parallel_for_selftests ()
  89 {
  90 #ifdef CXX_STD_THREAD
  91   selftests::register_test ("parallel_for",
  92                             selftests::parallel_for::test_n_threads);
  93 #endif /* CXX_STD_THREAD */
  94 }
  95
  96 #else /* FOR_EACH */
  97
  98 static void
  99 TEST (int n_threads)
 100 {
 101   save_restore_n_threads saver;
 102   gdb::thread_pool::g_thread_pool->set_thread_count (n_threads);
 103
 104 #define NUMBER 10000
 105
 106   std::atomic<int> counter (0);
 107   FOR_EACH (1, 0, NUMBER,
 108             [&] (int start, int end)
 109             {
 110               counter += end - start;
 111             });
 112   SELF_CHECK (counter == NUMBER);
 113
 114   counter = 0;
 115   FOR_EACH (1, 0, 0,
 116             [&] (int start, int end)
 117             {
 118               counter += end - start;
 119             });
 120   SELF_CHECK (counter == 0);
 121
 122 #undef NUMBER
 123
 124   /* Check that if there are fewer tasks than threads, then we won't
 125      end up with a null result.  */
 126   std::vector<std::unique_ptr<int>> intresults;
 127   std::atomic<bool> any_empty_tasks (false);
 128
 129   FOR_EACH (1, 0, 1,
 130             [&] (int start, int end)
 131               {
 132                 if (start == end)
 133                   any_empty_tasks = true;
 134                 return std::make_unique<int> (end - start);
 135               });
 136   SELF_CHECK (!any_empty_tasks);
 137   SELF_CHECK (std::all_of (intresults.begin (),
 138                            intresults.end (),
 139                            [] (const std::unique_ptr<int> &entry)
 140                              {
 141                                return entry != nullptr;
 142                              }));
 143 }
 144
 145 #endif /* FOR_EACH */