[glib] Bug 548967 - 1 bit mutex lock: add tests

[Ryan Lortie <ryanl src gnome org>]

commit 40eae351b1a95626f49ea042e5f5e9824c171c50
Author: Ryan Lortie <desrt desrt ca>
Date:   Thu Jan 28 18:41:19 2010 -0500

    Bug 548967 - 1 bit mutex lock: add tests
    
    Add a test case for the new API.
    
    Always check the emulated futex(2) implementation, even on systems with
    futex support.

 configure.in               |    1 +
 glib/gbitlock.c            |    4 ++
 gthread/Makefile.am        |    3 +
 gthread/tests/.gitignore   |    2 +
 gthread/tests/1bit-mutex.c |  127 ++++++++++++++++++++++++++++++++++++++++++++
 gthread/tests/Makefile.am  |   15 +++++
 6 files changed, 152 insertions(+), 0 deletions(-)
---
diff --git a/configure.in b/configure.in
index bda92e8..f30b05f 100644
--- a/configure.in
+++ b/configure.in
@@ -3531,6 +3531,7 @@ gobject/Makefile
 gobject/glib-mkenums
 gobject/tests/Makefile
 gthread/Makefile
+gthread/tests/Makefile
 gio/Makefile
 gio/xdgmime/Makefile
 gio/inotify/Makefile
diff --git a/glib/gbitlock.c b/glib/gbitlock.c
index 5181b11..b2ea9b5 100644
--- a/glib/gbitlock.c
+++ b/glib/gbitlock.c
@@ -31,6 +31,10 @@
 
 #include "galias.h"
 
+#ifdef G_BIT_LOCK_FORCE_FUTEX_EMULATION
+#undef HAVE_FUTEX
+#endif
+
 #ifndef HAVE_FUTEX
 static GSList *g_futex_address_list = NULL;
 static GMutex *g_futex_mutex = NULL;
diff --git a/gthread/Makefile.am b/gthread/Makefile.am
index de630e7..8252260 100644
--- a/gthread/Makefile.am
+++ b/gthread/Makefile.am
@@ -1,6 +1,9 @@
 ## Process this file with automake to produce Makefile.in
 include $(top_srcdir)/Makefile.decl
 
+SUBDIRS = . tests
+DIST_SUBDIRS = tests
+
 AM_CPPFLAGS = 				\
 	-I$(top_srcdir) 		\
 	-I$(top_srcdir)/glib 		\
diff --git a/gthread/tests/.gitignore b/gthread/tests/.gitignore
new file mode 100644
index 0000000..ad7fa10
--- /dev/null
+++ b/gthread/tests/.gitignore
@@ -0,0 +1,2 @@
+1bit-mutex
+1bit-emufutex
diff --git a/gthread/tests/1bit-mutex.c b/gthread/tests/1bit-mutex.c
new file mode 100644
index 0000000..dff095c
--- /dev/null
+++ b/gthread/tests/1bit-mutex.c
@@ -0,0 +1,127 @@
+/*
+ * 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 */
+  #define DISABLE_VISIBILITY
+  #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 ();
+
+  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 ();
+}
diff --git a/gthread/tests/Makefile.am b/gthread/tests/Makefile.am
new file mode 100644
index 0000000..c5fb653
--- /dev/null
+++ b/gthread/tests/Makefile.am
@@ -0,0 +1,15 @@
+include $(top_srcdir)/Makefile.decl
+
+INCLUDES = -g -I$(top_srcdir) -I$(top_srcdir)/glib $(GLIB_DEBUG_FLAGS)
+
+noinst_PROGRAMS = $(TEST_PROGS)
+progs_ldadd     = $(top_builddir)/glib/libglib-2.0.la \
+		  $(top_builddir)/gthread/libgthread-2.0.la
+
+TEST_PROGS	 += 1bit-mutex
+1bit_mutex_LDADD  = $(progs_ldadd) $(top_builddir)/gthread/libgthread-2.0.la
+
+TEST_PROGS	      += 1bit-emufutex
+1bit_emufutex_SOURCES  = 1bit-mutex.c
+1bit_emufutex_CFLAGS   = -DTEST_EMULATED_FUTEX
+1bit_emufutex_LDADD    = $(progs_ldadd) $(top_builddir)/gthread/libgthread-2.0.la