Subject: bug#26441: [PATCH] gnu: libunistring: Fix make check issues on multi-core machines.

From: Mathieu Othacehe <[email-masked]>
Date: Thu, 13 Apr 2017 18:33:40 +0200

* gnu/packages/patches/libunistring-gnulib-multi-core.patch: New file.
* gnu/packages/libunistring.scm (libunistring)[patches]: Add a reference
to previous patch.
---
 gnu/packages/libunistring.scm                      |   8 +-
 .../patches/libunistring-gnulib-multi-core.patch   | 178 +++++++++++++++++++++
 2 files changed, 185 insertions(+), 1 deletion(-)
 create mode 100644 gnu/packages/patches/libunistring-gnulib-multi-core.patch

diff --git a/gnu/packages/libunistring.scm b/gnu/packages/libunistring.scm
index 212bec4b4..df02f68ce 100644
--- a/gnu/packages/libunistring.scm
+++ b/gnu/packages/libunistring.scm
@@ -3,6 +3,7 @@
 ;;; Copyright © 2015 Mark H Weaver <[email-masked]>
 ;;; Copyright © 2016 Efraim Flashner <[email-masked]>
 ;;; Copyright © 2016 Jan Nieuwenhuizen <[email-masked]>
+;;; Copyright © 2017 Mathieu Othacehe <[email-masked]>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -24,6 +25,7 @@
   #:use-module (guix packages)
   #:use-module (guix download)
   #:use-module (guix build-system gnu)
+  #:use-module (gnu packages)
   #:use-module (gnu packages base))
 
 (define-public libunistring
@@ -37,7 +39,11 @@
                   version ".tar.xz"))
             (sha256
              (base32
-              "15z76qrmrvkc3c6hfq2lzzqysgd21s682f2smycfab5g598n8drf"))))
+              "15z76qrmrvkc3c6hfq2lzzqysgd21s682f2smycfab5g598n8drf"))
+             ;; test-lock has performance issues on multi-core machines,
+             ;; it hangs or takes a long time to complete.
+             ;; This is a commit from gnulib to fix this issue.
+            (patches (search-patches "libunistring-gnulib-multi-core.patch"))))
    (propagated-inputs (libiconv-if-needed))
    (build-system gnu-build-system)
    (arguments
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 000000000..709b20c6d
--- /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 <[email-masked]>.
+
+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 ();
+ }
-- 
2.12.2