glib/tests/1bit-mutex.c

   1 /*
   2  * Copyright © 2008 Ryan Lortie
   3  * Copyright © 2010 Codethink Limited
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public License as
   7  * published by the Free Software Foundation; either version 2 of the
   8  * License, or (at your option) any later version.
   9  *
  10  * See the included COPYING file for more information.
  11  */
  12
  13 #include "config.h"
  14
  15 /* LOCKS should be more than the number of contention
  16  * counters in gthread.c in order to ensure we exercise
  17  * the case where they overlap.
  18  */
  19 #define LOCKS      48
  20 #define ITERATIONS 10000
  21 #define THREADS    100
  22
  23 #include <glib.h>
  24
  25 #if TEST_EMULATED_FUTEX
  26
  27 #pragma GCC diagnostic push
  28 #pragma GCC diagnostic ignored "-Wmissing-prototypes"
  29
  30   /* this is defined for the 1bit-mutex-emufutex test.
  31    *
  32    * we want to test the emulated futex even if futex(2) is available.
  33    */
  34
  35   /* side-step some glib build stuff */
  36   #define GLIB_COMPILATION
  37
  38   /* rebuild gbitlock.c without futex support,
  39      defining our own version of the g_bit_*lock symbols
  40    */
  41   #undef g_pointer_bit_lock
  42   #undef g_pointer_bit_trylock
  43   #undef g_pointer_bit_unlock
  44
  45   #define g_bit_lock            _emufutex_g_bit_lock
  46   #define g_bit_trylock         _emufutex_g_bit_trylock
  47   #define g_bit_unlock          _emufutex_g_bit_unlock
  48   #define g_pointer_bit_lock    _emufutex_g_pointer_bit_lock
  49   #define g_pointer_bit_trylock _emufutex_g_pointer_bit_trylock
  50   #define g_pointer_bit_unlock  _emufutex_g_pointer_bit_unlock
  51
  52   #define G_BIT_LOCK_FORCE_FUTEX_EMULATION
  53
  54   #include <glib/gbitlock.c>
  55
  56 #pragma GCC diagnostic pop
  57 #endif
  58
  59 volatile GThread *owners[LOCKS];
  60 volatile gint     locks[LOCKS];
  61 volatile gpointer ptrs[LOCKS];
  62 volatile gint     bits[LOCKS];
  63
  64 static void
  65 acquire (int      nr,
  66          gboolean use_pointers)
  67 {
  68   GThread *self;
  69
  70   self = g_thread_self ();
  71
  72   g_assert_cmpint (((gsize) ptrs) % sizeof(gint), ==, 0);
  73
  74   if (!(use_pointers ?
  75           g_pointer_bit_trylock (&ptrs[nr], bits[nr])
  76         : g_bit_trylock (&locks[nr], bits[nr])))
  77     {
  78       if (g_test_verbose ())
  79         g_print ("thread %p going to block on lock %d\n", self, nr);
  80
  81       if (use_pointers)
  82         g_pointer_bit_lock (&ptrs[nr], bits[nr]);
  83       else
  84         g_bit_lock (&locks[nr], bits[nr]);
  85     }
  86
  87   g_assert (owners[nr] == NULL);   /* hopefully nobody else is here */
  88   owners[nr] = self;
  89
  90   /* let some other threads try to ruin our day */
  91   g_thread_yield ();
  92   g_thread_yield ();
  93   g_thread_yield ();
  94
  95   g_assert (owners[nr] == self);   /* hopefully this is still us... */
  96   owners[nr] = NULL;               /* make way for the next guy */
  97
  98   if (use_pointers)
  99     g_pointer_bit_unlock (&ptrs[nr], bits[nr]);
 100   else
 101     g_bit_unlock (&locks[nr], bits[nr]);
 102 }
 103
 104 static gpointer
 105 thread_func (gpointer data)
 106 {
 107   gboolean use_pointers = GPOINTER_TO_INT (data);
 108   gint i;
 109   GRand *rand;
 110
 111   rand = g_rand_new ();
 112
 113   for (i = 0; i < ITERATIONS; i++)
 114     acquire (g_rand_int_range (rand, 0, LOCKS), use_pointers);
 115
 116   g_rand_free (rand);
 117
 118   return NULL;
 119 }
 120
 121 static void
 122 testcase (gconstpointer data)
 123 {
 124   gboolean use_pointers = GPOINTER_TO_INT (data);
 125   GThread *threads[THREADS];
 126   int i;
 127
 128 #ifdef TEST_EMULATED_FUTEX
 129   #define SUFFIX "-emufutex"
 130
 131   /* ensure that we are using the emulated futex by checking
 132    * (at compile-time) for the existance of 'g_futex_address_list'
 133    */
 134   g_assert (g_futex_address_list == NULL);
 135 #else
 136   #define SUFFIX ""
 137 #endif
 138
 139   for (i = 0; i < LOCKS; i++)
 140     bits[i] = g_random_int () % 32;
 141
 142   for (i = 0; i < THREADS; i++)
 143     threads[i] = g_thread_new ("foo", thread_func,
 144                                GINT_TO_POINTER (use_pointers));
 145
 146   for (i = 0; i < THREADS; i++)
 147     g_thread_join (threads[i]);
 148
 149   for (i = 0; i < LOCKS; i++)
 150     {
 151       g_assert (owners[i] == NULL);
 152       g_assert (locks[i] == 0);
 153     }
 154 }
 155
 156 int
 157 main (int argc, char **argv)
 158 {
 159   g_test_init (&argc, &argv, NULL);
 160
 161   g_test_add_data_func ("/glib/1bit-mutex" SUFFIX "/int", (gpointer) 0, testcase);
 162   g_test_add_data_func ("/glib/1bit-mutex" SUFFIX "/pointer", (gpointer) 1, testcase);
 163
 164   return g_test_run ();
 165 }