1 files changed, 178 insertions, 0 deletions
diff --git a/gnu/packages/patches/libunistring-gnulib-multi-core.patch b/gnu/packages/patches/libunistring-gnulib-multi-core.patch
new file mode 100644
index 0000000000..709b20c6d2
--- /dev/null
+++ b/gnu/packages/patches/libunistring-gnulib-multi-core.patch
@@ -0,0 +1,178 @@
+This patch fixes performance problems on multi-core machines
+as reported at <https://bugs.gnu.org/26441>.
+
+See commit 480d374e596a0ee3fed168ab42cd84c313ad3c89 in Gnulib
+by Bruno Haible <bruno@clisp.org>.
+
+diff --git a/tests/test-lock.c b/tests/test-lock.c
+index cb734b4e6..aa6de2739 100644
+--- a/tests/test-lock.c
++++ b/tests/test-lock.c
+@@ -50,6 +50,13 @@
+    Uncomment this to see if the operating system has a fair scheduler.  */
+ #define EXPLICIT_YIELD 1
+ 
++/* Whether to use 'volatile' on some variables that communicate information
++   between threads.  If set to 0, a lock is used to protect these variables.
++   If set to 1, 'volatile' is used; this is theoretically equivalent but can
++   lead to much slower execution (e.g. 30x slower total run time on a 40-core
++   machine.  */
++#define USE_VOLATILE 0
++
+ /* Whether to print debugging messages.  */
+ #define ENABLE_DEBUGGING 0
+ 
+@@ -103,6 +110,51 @@
+ # define yield()
+ #endif
+ 
++#if USE_VOLATILE
++struct atomic_int {
++  volatile int value;
++};
++static void
++init_atomic_int (struct atomic_int *ai)
++{
++}
++static int
++get_atomic_int_value (struct atomic_int *ai)
++{
++  return ai->value;
++}
++static void
++set_atomic_int_value (struct atomic_int *ai, int new_value)
++{
++  ai->value = new_value;
++}
++#else
++struct atomic_int {
++  gl_lock_define (, lock)
++  int value;
++};
++static void
++init_atomic_int (struct atomic_int *ai)
++{
++  gl_lock_init (ai->lock);
++}
++static int
++get_atomic_int_value (struct atomic_int *ai)
++{
++  gl_lock_lock (ai->lock);
++  int ret = ai->value;
++  gl_lock_unlock (ai->lock);
++  return ret;
++}
++static void
++set_atomic_int_value (struct atomic_int *ai, int new_value)
++{
++  gl_lock_lock (ai->lock);
++  ai->value = new_value;
++  gl_lock_unlock (ai->lock);
++}
++#endif
++
+ #define ACCOUNT_COUNT 4
+ 
+ static int account[ACCOUNT_COUNT];
+@@ -170,12 +222,12 @@ lock_mutator_thread (void *arg)
+   return NULL;
+ }
+ 
+-static volatile int lock_checker_done;
++static struct atomic_int lock_checker_done;
+ 
+ static void *
+ lock_checker_thread (void *arg)
+ {
+-  while (!lock_checker_done)
++  while (get_atomic_int_value (&lock_checker_done) == 0)
+     {
+       dbgprintf ("Checker %p before check lock\n", gl_thread_self_pointer ());
+       gl_lock_lock (my_lock);
+@@ -200,7 +252,8 @@ test_lock (void)
+   /* Initialization.  */
+   for (i = 0; i < ACCOUNT_COUNT; i++)
+     account[i] = 1000;
+-  lock_checker_done = 0;
++  init_atomic_int (&lock_checker_done);
++  set_atomic_int_value (&lock_checker_done, 0);
+ 
+   /* Spawn the threads.  */
+   checkerthread = gl_thread_create (lock_checker_thread, NULL);
+@@ -210,7 +263,7 @@ test_lock (void)
+   /* Wait for the threads to terminate.  */
+   for (i = 0; i < THREAD_COUNT; i++)
+     gl_thread_join (threads[i], NULL);
+-  lock_checker_done = 1;
++  set_atomic_int_value (&lock_checker_done, 1);
+   gl_thread_join (checkerthread, NULL);
+   check_accounts ();
+ }
+@@ -254,12 +307,12 @@ rwlock_mutator_thread (void *arg)
+   return NULL;
+ }
+ 
+-static volatile int rwlock_checker_done;
++static struct atomic_int rwlock_checker_done;
+ 
+ static void *
+ rwlock_checker_thread (void *arg)
+ {
+-  while (!rwlock_checker_done)
++  while (get_atomic_int_value (&rwlock_checker_done) == 0)
+     {
+       dbgprintf ("Checker %p before check rdlock\n", gl_thread_self_pointer ());
+       gl_rwlock_rdlock (my_rwlock);
+@@ -284,7 +337,8 @@ test_rwlock (void)
+   /* Initialization.  */
+   for (i = 0; i < ACCOUNT_COUNT; i++)
+     account[i] = 1000;
+-  rwlock_checker_done = 0;
++  init_atomic_int (&rwlock_checker_done);
++  set_atomic_int_value (&rwlock_checker_done, 0);
+ 
+   /* Spawn the threads.  */
+   for (i = 0; i < THREAD_COUNT; i++)
+@@ -295,7 +349,7 @@ test_rwlock (void)
+   /* Wait for the threads to terminate.  */
+   for (i = 0; i < THREAD_COUNT; i++)
+     gl_thread_join (threads[i], NULL);
+-  rwlock_checker_done = 1;
++  set_atomic_int_value (&rwlock_checker_done, 1);
+   for (i = 0; i < THREAD_COUNT; i++)
+     gl_thread_join (checkerthreads[i], NULL);
+   check_accounts ();
+@@ -356,12 +410,12 @@ reclock_mutator_thread (void *arg)
+   return NULL;
+ }
+ 
+-static volatile int reclock_checker_done;
++static struct atomic_int reclock_checker_done;
+ 
+ static void *
+ reclock_checker_thread (void *arg)
+ {
+-  while (!reclock_checker_done)
++  while (get_atomic_int_value (&reclock_checker_done) == 0)
+     {
+       dbgprintf ("Checker %p before check lock\n", gl_thread_self_pointer ());
+       gl_recursive_lock_lock (my_reclock);
+@@ -386,7 +440,8 @@ test_recursive_lock (void)
+   /* Initialization.  */
+   for (i = 0; i < ACCOUNT_COUNT; i++)
+     account[i] = 1000;
+-  reclock_checker_done = 0;
++  init_atomic_int (&reclock_checker_done);
++  set_atomic_int_value (&reclock_checker_done, 0);
+ 
+   /* Spawn the threads.  */
+   checkerthread = gl_thread_create (reclock_checker_thread, NULL);
+@@ -396,7 +451,7 @@ test_recursive_lock (void)
+   /* Wait for the threads to terminate.  */
+   for (i = 0; i < THREAD_COUNT; i++)
+     gl_thread_join (threads[i], NULL);
+-  reclock_checker_done = 1;
++  set_atomic_int_value (&reclock_checker_done, 1);
+   gl_thread_join (checkerthread, NULL);
+   check_accounts ();
+ }