Subject: bug#26441: [PATCH 2/3] gnu: findutils: Fix make check issues on multi-core machines.

From: Mathieu Othacehe <[email-masked]>
Date: Mon, 17 Apr 2017 12:18:28 +0200

* gnu/packages/patches/findutils-gnulib-multi-core.patch: New file.
* gnu/local.mk (dist_patch): Add previous patch.
* gnu/packages/base.scm (findutils)[patches]: Add a reference
to the previous patch.
---
 gnu/local.mk                                       |   1 +
 gnu/packages/base.scm                              |  10 +-
 .../patches/findutils-gnulib-multi-core.patch      | 294 +++++++++++++++++++++
 3 files changed, 303 insertions(+), 2 deletions(-)
 create mode 100644 gnu/packages/patches/findutils-gnulib-multi-core.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 620fb07f3..b1dbfec5e 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -562,6 +562,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/fcgi-2.4.0-gcc44-fixes.patch		\
   %D%/packages/patches/fcgi-2.4.0-poll.patch			\
   %D%/packages/patches/findutils-localstatedir.patch		\
+  %D%/packages/patches/findutils-gnulib-multi-core.patch	\
   %D%/packages/patches/findutils-test-xargs.patch		\
   %D%/packages/patches/flint-ldconfig.patch			\
   %D%/packages/patches/fltk-shared-lib-defines.patch		\
diff --git a/gnu/packages/base.scm b/gnu/packages/base.scm
index c56859021..004aacfa0 100644
--- a/gnu/packages/base.scm
+++ b/gnu/packages/base.scm
@@ -8,6 +8,7 @@
 ;;; Copyright © 2016 Efraim Flashner <[email-masked]>
 ;;; Copyright © 2016 Jan Nieuwenhuizen <[email-masked]>
 ;;; Copyright © 2017 Rene Saavedra <[email-masked]>
+;;; Copyright © 2017 Mathieu Othacehe <[email-masked]>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -259,8 +260,13 @@ interactive means to merge two files.")
             (sha256
              (base32
               "178nn4dl7wbcw499czikirnkniwnx36argdnqgz4ik9i6zvwkm6y"))
-            (patches (search-patches "findutils-localstatedir.patch"
-                                     "findutils-test-xargs.patch"))))
+            (patches (search-patches
+                      "findutils-localstatedir.patch"
+                      "findutils-test-xargs.patch"
+                      ;; 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.
+                      "findutils-gnulib-multi-core.patch"))))
    (build-system gnu-build-system)
    (arguments
     `(#:configure-flags (list
diff --git a/gnu/packages/patches/findutils-gnulib-multi-core.patch b/gnu/packages/patches/findutils-gnulib-multi-core.patch
new file mode 100644
index 000000000..5a37f4f1f
--- /dev/null
+++ b/gnu/packages/patches/findutils-gnulib-multi-core.patch
@@ -0,0 +1,294 @@
+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 a992f64..fb18dee 100644
+--- a/tests/test-lock.c
++++ b/tests/test-lock.c
+@@ -1,5 +1,5 @@
+ /* Test of locking in multithreaded situations.
+-   Copyright (C) 2005, 2008-2015 Free Software Foundation, Inc.
++   Copyright (C) 2005, 2008-2017 Free Software Foundation, Inc.
+ 
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+@@ -50,6 +50,28 @@
+    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 semaphore or 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), because 'volatile' does not imply any
++   synchronization/communication between different CPUs.  */
++#define USE_VOLATILE 0
++
++#if USE_POSIX_THREADS && HAVE_SEMAPHORE_H
++/* Whether to use a semaphore to communicate information between threads.
++   If set to 0, a lock is used. If set to 1, a semaphore is used.
++   Uncomment this to reduce the dependencies of this test.  */
++# define USE_SEMAPHORE 1
++/* Mac OS X provides only named semaphores (sem_open); its facility for
++   unnamed semaphores (sem_init) does not work.  */
++# if defined __APPLE__ && defined __MACH__
++#  define USE_NAMED_SEMAPHORE 1
++# else
++#  define USE_UNNAMED_SEMAPHORE 1
++# endif
++#endif
++
+ /* Whether to print debugging messages.  */
+ #define ENABLE_DEBUGGING 0
+ 
+@@ -90,6 +112,12 @@
+ 
+ #include "glthread/thread.h"
+ #include "glthread/yield.h"
++#if USE_SEMAPHORE
++# include <errno.h>
++# include <fcntl.h>
++# include <semaphore.h>
++# include <unistd.h>
++#endif
+ 
+ #if ENABLE_DEBUGGING
+ # define dbgprintf printf
+@@ -103,6 +131,132 @@
+ # 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;
++}
++#elif USE_SEMAPHORE
++/* This atomic_int implementation can only support the values 0 and 1.
++   It is initially 0 and can be set to 1 only once.  */
++# if USE_UNNAMED_SEMAPHORE
++struct atomic_int {
++  sem_t semaphore;
++};
++#define atomic_int_semaphore(ai) (&(ai)->semaphore)
++static void
++init_atomic_int (struct atomic_int *ai)
++{
++  sem_init (&ai->semaphore, 0, 0);
++}
++# endif
++# if USE_NAMED_SEMAPHORE
++struct atomic_int {
++  sem_t *semaphore;
++};
++#define atomic_int_semaphore(ai) ((ai)->semaphore)
++static void
++init_atomic_int (struct atomic_int *ai)
++{
++  sem_t *s;
++  unsigned int count;
++  for (count = 0; ; count++)
++    {
++      char name[80];
++      /* Use getpid() in the name, so that different processes running at the
++         same time will not interfere.  Use ai in the name, so that different
++         atomic_int in the same process will not interfere.  Use a count in
++         the name, so that even in the (unlikely) case that a semaphore with
++         the specified name already exists, we can try a different name.  */
++      sprintf (name, "test-lock-%lu-%p-%u",
++               (unsigned long) getpid (), ai, count);
++      s = sem_open (name, O_CREAT | O_EXCL, 0600, 0);
++      if (s == SEM_FAILED)
++        {
++          if (errno == EEXIST)
++            /* Retry with a different name.  */
++            continue;
++          else
++            {
++              perror ("sem_open failed");
++              abort ();
++            }
++        }
++      else
++        {
++          /* Try not to leave a semaphore hanging around on the file system
++             eternally, if we can avoid it.  */
++          sem_unlink (name);
++          break;
++        }
++    }
++  ai->semaphore = s;
++}
++# endif
++static int
++get_atomic_int_value (struct atomic_int *ai)
++{
++  if (sem_trywait (atomic_int_semaphore (ai)) == 0)
++    {
++      if (sem_post (atomic_int_semaphore (ai)))
++        abort ();
++      return 1;
++    }
++  else if (errno == EAGAIN)
++    return 0;
++  else
++    abort ();
++}
++static void
++set_atomic_int_value (struct atomic_int *ai, int new_value)
++{
++  if (new_value == 0)
++    /* It's already initialized with 0.  */
++    return;
++  /* To set the value 1: */
++  if (sem_post (atomic_int_semaphore (ai)))
++    abort ();
++}
++#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 +324,12 @@ 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 +354,8 @@ 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 +365,7 @@ 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 +409,12 @@ 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 +439,8 @@ 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 +451,7 @@ 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 +512,12 @@ 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 +542,8 @@ 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 +553,7 @@ 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