glib/gthread/tests/1bit-mutex.c

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/*
* Copyright © 2008 Ryan Lortie
* Copyright © 2010 Codethink Limited
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* See the included COPYING file for more information.
*/
/* LOCKS should be more than the number of contention
* counters in gthread.c in order to ensure we exercise
* the case where they overlap.
*/
#define LOCKS 48
#define ITERATIONS 10000
#define THREADS 100
#if TEST_EMULATED_FUTEX
/* this is defined for the 1bit-mutex-emufutex test.
*
* we want to test the emulated futex even if futex(2) is available.
*/
/* side-step some glib build stuff */
#ifndef DISABLE_VISIBILITY
#define DISABLE_VISIBILITY
#endif
#define GLIB_COMPILATION
/* rebuild gbitlock.c without futex support,
defining our own version of the g_bit_*lock symbols
*/
#define g_bit_lock _emufutex_g_bit_lock
#define g_bit_trylock _emufutex_g_bit_trylock
#define g_bit_unlock _emufutex_g_bit_unlock
#define _g_futex_thread_init _emufutex_g_futex_thread_init
#define G_BIT_LOCK_FORCE_FUTEX_EMULATION
#include <glib/gbitlock.c>
#endif
#include <glib.h>
volatile GThread *owners[LOCKS];
volatile gint locks[LOCKS];
volatile gint bits[LOCKS];
static void
acquire (int nr)
{
GThread *self;
self = g_thread_self ();
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if (!g_bit_trylock (&locks[nr], bits[nr]))
{
if (g_test_verbose ())
g_print ("thread %p going to block on lock %d\n", self, nr);
g_bit_lock (&locks[nr], bits[nr]);
}
g_assert (owners[nr] == NULL); /* hopefully nobody else is here */
owners[nr] = self;
/* let some other threads try to ruin our day */
g_thread_yield ();
g_thread_yield ();
g_thread_yield ();
g_assert (owners[nr] == self); /* hopefully this is still us... */
owners[nr] = NULL; /* make way for the next guy */
g_bit_unlock (&locks[nr], bits[nr]);
}
static gpointer
thread_func (gpointer data)
{
gint i;
for (i = 0; i < ITERATIONS; i++)
acquire (g_random_int () % LOCKS);
return NULL;
}
static void
testcase (void)
{
GThread *threads[THREADS];
int i;
g_thread_init (NULL);
#ifdef TEST_EMULATED_FUTEX
_g_futex_thread_init ();
#define SUFFIX "-emufutex"
/* ensure that we are using the emulated futex by checking
* (at compile-time) for the existance of 'g_futex_mutex'
*/
g_assert (g_futex_mutex != NULL);
#else
#define SUFFIX ""
#endif
for (i = 0; i < LOCKS; i++)
bits[i] = g_random_int () % 32;
for (i = 0; i < THREADS; i++)
threads[i] = g_thread_create (thread_func, NULL, TRUE, NULL);
for (i = 0; i < THREADS; i++)
g_thread_join (threads[i]);
for (i = 0; i < LOCKS; i++)
{
g_assert (owners[i] == NULL);
g_assert (locks[i] == 0);
}
}
int
main (int argc, char **argv)
{
g_test_init (&argc, &argv, NULL);
g_test_add_func ("/glib/1bit-mutex" SUFFIX, testcase);
return g_test_run ();
}