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 "defs.h"
  28 #include "gdbsupport/selftest.h"
  29 #include "gdbsupport/parallel-for.h"
  30
  31 #if CXX_STD_THREAD
  32
  33 #include "gdbsupport/thread-pool.h"
  34
  35 namespace selftests {
  36 namespace parallel_for {
  37
  38 struct save_restore_n_threads
  39 {
  40   save_restore_n_threads ()
  41     : n_threads (gdb::thread_pool::g_thread_pool->thread_count ())
  42   {
  43   }
  44
  45   ~save_restore_n_threads ()
  46   {
  47     gdb::thread_pool::g_thread_pool->set_thread_count (n_threads);
  48   }
  49
  50   int n_threads;
  51 };
  52
  53 /* Define test_par using TEST in the FOR_EACH-defined part.  */
  54 #define TEST test_par
  55 #define FOR_EACH gdb::parallel_for_each
  56 #include "parallel-for-selftests.c"
  57 #undef FOR_EACH
  58 #undef TEST
  59
  60 /* Define test_seq using TEST in the FOR_EACH-defined part.  */
  61 #define TEST test_seq
  62 #define FOR_EACH gdb::sequential_for_each
  63 #include "parallel-for-selftests.c"
  64 #undef FOR_EACH
  65 #undef TEST
  66
  67 static void
  68 test (int n_threads)
  69 {
  70   test_par (n_threads);
  71   test_seq (n_threads);
  72 }
  73
  74 static void
  75 test_n_threads ()
  76 {
  77   test (0);
  78   test (1);
  79   test (3);
  80 }
  81
  82 }
  83 }
  84
  85 #endif /* CXX_STD_THREAD */
  86
  87 void _initialize_parallel_for_selftests ();
  88 void
  89 _initialize_parallel_for_selftests ()
  90 {
  91 #ifdef CXX_STD_THREAD
  92   selftests::register_test ("parallel_for",
  93                             selftests::parallel_for::test_n_threads);
  94 #endif /* CXX_STD_THREAD */
  95 }
  96
  97 #else /* FOR_EACH */
  98
  99 static void
 100 TEST (int n_threads)
 101 {
 102   save_restore_n_threads saver;
 103   gdb::thread_pool::g_thread_pool->set_thread_count (n_threads);
 104
 105 #define NUMBER 10000
 106
 107   std::atomic<int> counter (0);
 108   FOR_EACH (1, 0, NUMBER,
 109             [&] (int start, int end)
 110             {
 111               counter += end - start;
 112             });
 113   SELF_CHECK (counter == NUMBER);
 114
 115   counter = 0;
 116   FOR_EACH (1, 0, 0,
 117             [&] (int start, int end)
 118             {
 119               counter += end - start;
 120             });
 121   SELF_CHECK (counter == 0);
 122
 123 #undef NUMBER
 124
 125   /* Check that if there are fewer tasks than threads, then we won't
 126      end up with a null result.  */
 127   std::vector<std::unique_ptr<int>> intresults;
 128   std::atomic<bool> any_empty_tasks (false);
 129
 130   FOR_EACH (1, 0, 1,
 131             [&] (int start, int end)
 132               {
 133                 if (start == end)
 134                   any_empty_tasks = true;
 135                 return std::make_unique<int> (end - start);
 136               });
 137   SELF_CHECK (!any_empty_tasks);
 138   SELF_CHECK (std::all_of (intresults.begin (),
 139                            intresults.end (),
 140                            [] (const std::unique_ptr<int> &entry)
 141                              {
 142                                return entry != nullptr;
 143                              }));
 144 }
 145
 146 #endif /* FOR_EACH */