New API to set default thread attributes

This patch introduces two new convenience functions to set the default
thread attributes used for creating threads.  This allows a programmer
to set the default thread attributes just once in a process and then
run pthread_create without additional attributes.

1 files changed, 385 insertions, 0 deletions

diff --git a/nptl/tst-default-attr.c b/nptl/tst-default-attr.c
new file mode 100644
index 0000000..d7e8611
--- /dev/null
+++ b/nptl/tst-default-attr.c
@@ -0,0 +1,385 @@
+/* Verify that pthread_[gs]etattr_default_np work correctly.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdbool.h>
+
+#define RETURN_IF_FAIL(f, ...) \
+  ({									      \
+    int ret = f (__VA_ARGS__);						      \
+    if (ret != 0)							      \
+      {									      \
+	printf ("%s:%d: %s returned %d (errno = %d)\n", __FILE__, __LINE__,   \
+		#f, ret, errno);					      \
+	return ret;							      \
+      }									      \
+  })
+
+static int (*verify_result) (pthread_attr_t *);
+static size_t stacksize = 1024 * 1024;
+static size_t guardsize;
+static bool do_join = true;
+static int running = 0;
+static int detach_failed = 0;
+static pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t c = PTHREAD_COND_INITIALIZER;
+
+static void *
+thr (void *unused __attribute__ ((unused)))
+{
+  pthread_attr_t attr;
+  int ret;
+
+  memset (&attr, 0xab, sizeof attr);
+  /* To verify that the pthread_setattr_default_np worked.  */
+  if ((ret = pthread_getattr_default_np (&attr)) != 0)
+    {
+      printf ("pthread_getattr_default_np failed: %s\n", strerror (ret));
+      goto out;
+    }
+
+  if ((ret = (*verify_result) (&attr)) != 0)
+    goto out;
+
+  memset (&attr, 0xab, sizeof attr);
+  /* To verify that the attributes actually got applied.  */
+  if ((ret = pthread_getattr_np (pthread_self (), &attr)) != 0)
+    {
+      printf ("pthread_getattr_default_np failed: %s\n", strerror (ret));
+      goto out;
+    }
+
+  ret = (*verify_result) (&attr);
+
+out:
+  if (!do_join)
+    {
+      pthread_mutex_lock (&m);
+      running--;
+      pthread_cond_signal (&c);
+      pthread_mutex_unlock (&m);
+
+      detach_failed |= ret;
+    }
+
+  return (void *) (uintptr_t) ret;
+}
+
+static int
+run_threads (const pthread_attr_t *attr)
+{
+  pthread_t t;
+  void *tret = NULL;
+
+  RETURN_IF_FAIL (pthread_setattr_default_np, attr);
+
+  /* Run twice to ensure that the attributes do not get overwritten in the
+     first run somehow.  */
+  for (int i = 0; i < 2; i++)
+    {
+      RETURN_IF_FAIL (pthread_create, &t, NULL, thr, NULL);
+      if (do_join)
+	RETURN_IF_FAIL (pthread_join, t, &tret);
+      else
+	{
+	  pthread_mutex_lock (&m);
+	  running++;
+	  pthread_mutex_unlock (&m);
+	}
+
+      if (tret != NULL)
+	{
+	  puts ("Thread failed");
+	  return 1;
+	}
+    }
+
+  /* Stay in sync for detached threads and get their status.  */
+  while (!do_join)
+    {
+      pthread_mutex_lock (&m);
+      if (running == 0)
+	{
+	  pthread_mutex_unlock (&m);
+	  break;
+	}
+      pthread_cond_wait (&c, &m);
+      pthread_mutex_unlock (&m);
+    }
+
+  return 0;
+}
+
+static int
+verify_detach_result (pthread_attr_t *attr)
+{
+  int state;
+
+  RETURN_IF_FAIL (pthread_attr_getdetachstate, attr, &state);
+
+  if (state != PTHREAD_CREATE_DETACHED)
+    {
+      puts ("failed to set detach state");
+      return 1;
+    }
+
+  return 0;
+}
+
+static int
+do_detach_test (void)
+{
+  pthread_attr_t attr;
+
+  do_join = false;
+  RETURN_IF_FAIL (pthread_attr_init, &attr);
+  RETURN_IF_FAIL (pthread_attr_setdetachstate, &attr, PTHREAD_CREATE_DETACHED);
+
+  RETURN_IF_FAIL (run_threads, &attr);
+  return detach_failed;
+}
+
+static int
+verify_affinity_result (pthread_attr_t *attr)
+{
+  cpu_set_t cpuset;
+
+  RETURN_IF_FAIL (pthread_attr_getaffinity_np, attr, sizeof (cpuset), &cpuset);
+  if (!CPU_ISSET (0, &cpuset))
+    {
+      puts ("failed to set cpu affinity");
+      return 1;
+    }
+
+  return 0;
+}
+
+static int
+do_affinity_test (void)
+{
+  pthread_attr_t attr;
+
+  RETURN_IF_FAIL (pthread_attr_init, &attr);
+
+  /* Processor affinity.  Like scheduling policy, this could fail if the user
+     does not have the necessary privileges.  So we only spew a warning if
+     pthread_create fails with EPERM.  A computer has at least one CPU.  */
+  cpu_set_t cpuset;
+  CPU_ZERO (&cpuset);
+  CPU_SET (0, &cpuset);
+  RETURN_IF_FAIL (pthread_attr_setaffinity_np, &attr, sizeof (cpuset), &cpuset);
+
+  int ret = run_threads (&attr);
+
+  if (ret == EPERM)
+    {
+      printf ("Skipping CPU Affinity test: %s\n", strerror (ret));
+      return 0;
+    }
+  else if (ret != 0)
+    return ret;
+
+  return 0;
+}
+
+static int
+verify_sched_result (pthread_attr_t *attr)
+{
+  int inherited, policy;
+  struct sched_param param;
+
+  RETURN_IF_FAIL (pthread_attr_getinheritsched, attr, &inherited);
+  if (inherited != PTHREAD_EXPLICIT_SCHED)
+    {
+      puts ("failed to set EXPLICIT_SCHED (%d != %d)");
+      return 1;
+    }
+
+  RETURN_IF_FAIL (pthread_attr_getschedpolicy, attr, &policy);
+  if (policy != SCHED_RR)
+    {
+      printf ("failed to set SCHED_RR (%d != %d)\n", policy, SCHED_RR);
+      return 1;
+    }
+
+  RETURN_IF_FAIL (pthread_attr_getschedparam, attr, &param);
+  if (param.sched_priority != 42)
+    {
+      printf ("failed to set sched_priority (%d != %d)\n",
+	      param.sched_priority, 42);
+      return 1;
+    }
+
+  return 0;
+}
+
+static int
+do_sched_test (void)
+{
+  pthread_attr_t attr;
+
+  RETURN_IF_FAIL (pthread_attr_init, &attr);
+
+  /* Scheduling policy.  Note that we don't always test these since it's
+     possible that the user the tests run as don't have the appropriate
+     privileges.  */
+  RETURN_IF_FAIL (pthread_attr_setinheritsched, &attr, PTHREAD_EXPLICIT_SCHED);
+  RETURN_IF_FAIL (pthread_attr_setschedpolicy, &attr, SCHED_RR);
+
+  struct sched_param param;
+  param.sched_priority = 42;
+  RETURN_IF_FAIL (pthread_attr_setschedparam, &attr, &param);
+
+  int ret = run_threads (&attr);
+
+  if (ret == EPERM)
+    {
+      printf ("Skipping Scheduler Attributes test: %s\n", strerror (ret));
+      return 0;
+    }
+  else if (ret != 0)
+    return ret;
+
+  return 0;
+}
+
+static int
+verify_guardsize_result (pthread_attr_t *attr)
+{
+  size_t guard;
+
+  RETURN_IF_FAIL (pthread_attr_getguardsize, attr, &guard);
+
+  if (guardsize != guard)
+    {
+      printf ("failed to set guardsize (%zu, %zu)\n", guardsize, guard);
+      return 1;
+    }
+
+  return 0;
+}
+
+static int
+do_guardsize_test (void)
+{
+  long int pagesize = sysconf (_SC_PAGESIZE);
+  pthread_attr_t attr;
+
+  if (pagesize < 0)
+    {
+      printf ("sysconf failed: %s\n", strerror (errno));
+      return 1;
+    }
+
+  RETURN_IF_FAIL (pthread_getattr_default_np, &attr);
+
+  /* Increase default guardsize by a page.  */
+  RETURN_IF_FAIL (pthread_attr_getguardsize, &attr, &guardsize);
+  guardsize += pagesize;
+  RETURN_IF_FAIL (pthread_attr_setguardsize, &attr, guardsize);
+  RETURN_IF_FAIL (run_threads, &attr);
+
+  return 0;
+}
+
+static int
+verify_stacksize_result (pthread_attr_t *attr)
+{
+  size_t stack;
+
+  RETURN_IF_FAIL (pthread_attr_getstacksize, attr, &stack);
+
+  if (stacksize != stack)
+    {
+      printf ("failed to set default stacksize (%zu, %zu)\n", stacksize, stack);
+      return 1;
+    }
+
+  return 0;
+}
+
+static int
+do_stacksize_test (void)
+{
+  long int pagesize = sysconf (_SC_PAGESIZE);
+  pthread_attr_t attr;
+
+  if (pagesize < 0)
+    {
+      printf ("sysconf failed: %s\n", strerror (errno));
+      return 1;
+    }
+
+  /* Perturb the size by a page so that we're not aligned on the 64K boundary.
+     pthread_create does this perturbation on x86 to avoid causing the 64k
+     aliasing conflict.  We want to prevent pthread_create from doing that
+     since it is not consistent for all architectures.  */
+  stacksize += pagesize;
+
+  RETURN_IF_FAIL (pthread_attr_init, &attr);
+
+  /* Run twice to ensure that we don't give a false positive.  */
+  RETURN_IF_FAIL (pthread_attr_setstacksize, &attr, stacksize);
+  RETURN_IF_FAIL (run_threads, &attr);
+  stacksize *= 2;
+  RETURN_IF_FAIL (pthread_attr_setstacksize, &attr, stacksize);
+  RETURN_IF_FAIL (run_threads, &attr);
+  return 0;
+}
+
+/* We test each attribute separately because sched and affinity tests may need
+   additional user privileges that may not be available during the test run.
+   Each attribute test is a set of two functions, viz. a function to set the
+   default attribute (do_foo_test) and another to verify its result
+   (verify_foo_result).  Each test spawns a thread and checks (1) if the
+   attribute values were applied correctly and (2) if the change in the default
+   value reflected.  */
+static int
+do_test (void)
+{
+  puts ("stacksize test");
+  verify_result = verify_stacksize_result;
+  RETURN_IF_FAIL (do_stacksize_test);
+
+  puts ("guardsize test");
+  verify_result = verify_guardsize_result;
+  RETURN_IF_FAIL (do_guardsize_test);
+
+  puts ("sched test");
+  verify_result = verify_sched_result;
+  RETURN_IF_FAIL (do_sched_test);
+
+  puts ("affinity test");
+  verify_result = verify_affinity_result;
+  RETURN_IF_FAIL (do_affinity_test);
+
+  puts ("detach test");
+  verify_result = verify_detach_result;
+  RETURN_IF_FAIL (do_detach_test);
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"