These tests that hammer shared_ptr and weak_ptr to test the
thread-safety of the reference counting were originally written for
the TR1 smart pointers, and so pre-date std::thread etc.
This refactors them to use C++11 std::thread and std::atomic (with
relaxed memory ordering, since we don't need to know the counter value
until after we've joined all the worker threads).
I also used the std::mt19937 typedef that uses the same parameters as
the test lists explicitly (mt19937 produces uint_fast32_t not unsigned
long, but that doesn't change anything here) and replaced the
non-uniform modulus operation with std::uniform_int_distribution.
To verify that after the changes we still test what we're trying to
test, I changed the shared_ptr code to remove the synchronization in
_M_add_ref_lock and saw the tests fail.
* testsuite/20_util/shared_ptr/thread/default_weaktoshared.cc: Use
std::mt19937, std::thread and std::atomic to simplify test.
* testsuite/20_util/shared_ptr/thread/mutex_weaktoshared.cc: Likewise.
Tested x86_64-linux (8 HT cores) and powerpc64-linux (160 cores).
Committed to trunk.
commit b2f86d9d04f9561b5189eccaa85e5d2b21884de4
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Mon Jul 25 10:32:11 2016 +0100
Use std::mt19937, std::thread and std::atomic to simplify tests
* testsuite/20_util/shared_ptr/thread/default_weaktoshared.cc: Use
std::mt19937, std::thread and std::atomic to simplify test.
* testsuite/20_util/shared_ptr/thread/mutex_weaktoshared.cc: Likewise.
diff --git
a/libstdc++-v3/testsuite/20_util/shared_ptr/thread/default_weaktoshared.cc
b/libstdc++-v3/testsuite/20_util/shared_ptr/thread/default_weaktoshared.cc
index d5b9d4f..a853307 100644
--- a/libstdc++-v3/testsuite/20_util/shared_ptr/thread/default_weaktoshared.cc
+++ b/libstdc++-v3/testsuite/20_util/shared_ptr/thread/default_weaktoshared.cc
@@ -25,11 +25,11 @@
#include <memory>
#include <random>
#include <vector>
-#include <testsuite_hooks.h>
#include <iostream>
#include <cstdlib>
-
-#include <pthread.h>
+#include <thread>
+#include <atomic>
+#include <testsuite_hooks.h>
#ifdef _GLIBCXX_HAVE_UNISTD_H
#include <unistd.h> // To test for _POSIX_THREAD_PRIORITY_SCHEDULING
@@ -50,19 +50,13 @@ const unsigned long HAMMER_REPEAT = 100000;
const unsigned long KILL_ONE_IN = 1000;
struct A
- {
- static _Atomic_word counter;
- A()
- {
- __gnu_cxx::__atomic_add(&counter, 1);
- }
- ~A()
- {
- __gnu_cxx::__atomic_add(&counter, -1);
- }
- };
+{
+ static std::atomic<int> counter;
+ A() { counter.fetch_add(1, std::memory_order_relaxed); }
+ ~A() { counter.fetch_sub(1, std::memory_order_relaxed); }
+};
-_Atomic_word A::counter = 0;
+std::atomic<int> A::counter{ 0 };
typedef std::shared_ptr<A> sp_A_t;
typedef std::weak_ptr<A> wp_A_t;
@@ -80,16 +74,10 @@ struct shared_and_weak_pools
{ }
};
-void* thread_hammer_and_kill(void* opaque_pools)
+void thread_hammer_and_kill(shared_and_weak_pools& pools)
{
- shared_and_weak_pools& pools =
*static_cast<shared_and_weak_pools*>(opaque_pools);
- // Using the same parameters as in the RNG test cases.
- std::mersenne_twister_engine<
- unsigned long, 32, 624, 397, 31,
- 0x9908b0dful, 11,
- 0xfffffffful, 7,
- 0x9d2c5680ul, 15,
- 0xefc60000ul, 18, 1812433253ul> rng;
+ std::mt19937 urbg;
+ std::uniform_int_distribution<> dist(0, KILL_ONE_IN - 1);
sp_vector_t::iterator cur_shared = pools.shared_pool.begin();
wp_vector_t::iterator cur_weak = pools.weak_pool.begin();
@@ -107,26 +95,16 @@ void* thread_hammer_and_kill(void* opaque_pools)
break;
}
- if (rng() % KILL_ONE_IN == 0)
+ if (dist(urbg) == 0)
{
cur_shared->reset();
++cur_shared;
}
}
- return 0;
}
-void* thread_hammer(void* opaque_weak)
+void thread_hammer(wp_vector_t& weak_pool)
{
- wp_vector_t& weak_pool = *static_cast<wp_vector_t*>(opaque_weak);
- // Using the same parameters as in the RNG test cases.
- std::mersenne_twister_engine<
- unsigned long, 32, 624, 397, 31,
- 0x9908b0dful, 11,
- 0xfffffffful, 7,
- 0x9d2c5680ul, 15,
- 0xefc60000ul, 18, 1812433253ul> rng;
-
wp_vector_t::iterator cur_weak = weak_pool.begin();
for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
@@ -142,51 +120,38 @@ void* thread_hammer(void* opaque_weak)
break;
}
}
- return 0;
}
-int
+void
test01()
{
bool test __attribute__((unused)) = true;
sp_vector_t obj_pool(POOL_SIZE);
- for(sp_vector_t::iterator cur = obj_pool.begin(); cur != obj_pool.end();
++cur)
- {
- cur->reset(new A);
- }
+ for(auto& obj : obj_pool)
+ obj.reset(new A);
+
// Obtain weak references.
std::vector<wp_vector_t> weak_pool(HAMMER_MAX_THREADS,
wp_vector_t(obj_pool.begin(), obj_pool.end()));
// Launch threads with pointer to weak reference.
- pthread_t threads[HAMMER_MAX_THREADS];
+ std::thread threads[HAMMER_MAX_THREADS];
#if defined(__sun) && defined(__svr4__) && _XOPEN_VERSION >= 500
pthread_setconcurrency (HAMMER_MAX_THREADS);
#endif
- pthread_attr_t tattr;
- pthread_attr_init(&tattr);
-
shared_and_weak_pools pools(obj_pool, weak_pool[0]);
- pthread_create(threads, &tattr, thread_hammer_and_kill,
static_cast<void*>(&pools));
+ threads[0] = std::thread(thread_hammer_and_kill, std::ref(pools));
for (unsigned int worker = 1; worker < HAMMER_MAX_THREADS; worker++)
- {
- if (pthread_create(&threads[worker], &tattr,
- thread_hammer, static_cast<void*>(&weak_pool[worker])))
- std::abort();
- }
+ threads[worker] = std::thread(thread_hammer, std::ref(weak_pool[worker]));
+
// Wait for threads to complete, then check integrity of reference.
- void* status;
- for (unsigned int worker = 0; worker < HAMMER_MAX_THREADS; worker++)
- {
- if (pthread_join(threads[worker], &status))
- std::abort();
- }
+ for (auto& thread : threads)
+ thread.join();
+
obj_pool.clear();
VERIFY( A::counter == 0 );
-
- return 0;
}
int
diff --git
a/libstdc++-v3/testsuite/20_util/shared_ptr/thread/mutex_weaktoshared.cc
b/libstdc++-v3/testsuite/20_util/shared_ptr/thread/mutex_weaktoshared.cc
index 9a01716..404fc46 100644
--- a/libstdc++-v3/testsuite/20_util/shared_ptr/thread/mutex_weaktoshared.cc
+++ b/libstdc++-v3/testsuite/20_util/shared_ptr/thread/mutex_weaktoshared.cc
@@ -25,11 +25,11 @@
#include <memory>
#include <random>
#include <vector>
-#include <testsuite_hooks.h>
#include <iostream>
#include <cstdlib>
-
-#include <pthread.h>
+#include <thread>
+#include <atomic>
+#include <testsuite_hooks.h>
#ifdef _GLIBCXX_HAVE_UNISTD_H
#include <unistd.h> // To test for _POSIX_THREAD_PRIORITY_SCHEDULING
@@ -50,19 +50,13 @@ const unsigned long HAMMER_REPEAT = 100000;
const unsigned long KILL_ONE_IN = 1000;
struct A
- {
- static _Atomic_word counter;
- A()
- {
- __gnu_cxx::__atomic_add(&counter, 1);
- }
- ~A()
- {
- __gnu_cxx::__atomic_add(&counter, -1);
- }
- };
+{
+ static std::atomic<int> counter;
+ A() { counter.fetch_add(1, std::memory_order_relaxed); }
+ ~A() { counter.fetch_sub(1, std::memory_order_relaxed); }
+};
-_Atomic_word A::counter = 0;
+std::atomic<int> A::counter{0};
using std::_S_mutex;
@@ -82,16 +76,10 @@ struct shared_and_weak_pools
{ }
};
-void* thread_hammer_and_kill(void* opaque_pools)
+void thread_hammer_and_kill(shared_and_weak_pools& pools)
{
- shared_and_weak_pools& pools =
*static_cast<shared_and_weak_pools*>(opaque_pools);
- // Using the same parameters as in the RNG test cases.
- std::mersenne_twister_engine<
- unsigned long, 32, 624, 397, 31,
- 0x9908b0dful, 11,
- 0xfffffffful, 7,
- 0x9d2c5680ul, 15,
- 0xefc60000ul, 18, 1812433253ul> rng;
+ std::mt19937 urbg;
+ std::uniform_int_distribution<> dist(0, KILL_ONE_IN - 1);
sp_vector_t::iterator cur_shared = pools.shared_pool.begin();
wp_vector_t::iterator cur_weak = pools.weak_pool.begin();
@@ -109,26 +97,16 @@ void* thread_hammer_and_kill(void* opaque_pools)
break;
}
- if (rng() % KILL_ONE_IN == 0)
+ if (dist(urbg) == 0)
{
cur_shared->reset();
++cur_shared;
}
}
- return 0;
}
-void* thread_hammer(void* opaque_weak)
+void thread_hammer(wp_vector_t& weak_pool)
{
- wp_vector_t& weak_pool = *static_cast<wp_vector_t*>(opaque_weak);
- // Using the same parameters as in the RNG test cases.
- std::mersenne_twister_engine<
- unsigned long, 32, 624, 397, 31,
- 0x9908b0dful, 11,
- 0xfffffffful, 7,
- 0x9d2c5680ul, 15,
- 0xefc60000ul, 18, 1812433253ul> rng;
-
wp_vector_t::iterator cur_weak = weak_pool.begin();
for (unsigned int i = 0; i < HAMMER_REPEAT; ++i)
@@ -144,51 +122,38 @@ void* thread_hammer(void* opaque_weak)
break;
}
}
- return 0;
}
-int
+void
test01()
{
bool test __attribute__((unused)) = true;
sp_vector_t obj_pool(POOL_SIZE);
- for(sp_vector_t::iterator cur = obj_pool.begin(); cur != obj_pool.end();
++cur)
- {
- cur->reset(new A);
- }
+ for(auto& obj : obj_pool)
+ obj.reset(new A);
+
// Obtain weak references.
std::vector<wp_vector_t> weak_pool(HAMMER_MAX_THREADS,
wp_vector_t(obj_pool.begin(), obj_pool.end()));
// Launch threads with pointer to weak reference.
- pthread_t threads[HAMMER_MAX_THREADS];
+ std::thread threads[HAMMER_MAX_THREADS];
#if defined(__sun) && defined(__svr4__) && _XOPEN_VERSION >= 500
pthread_setconcurrency (HAMMER_MAX_THREADS);
#endif
- pthread_attr_t tattr;
- pthread_attr_init(&tattr);
-
shared_and_weak_pools pools(obj_pool, weak_pool[0]);
- pthread_create(threads, &tattr, thread_hammer_and_kill,
static_cast<void*>(&pools));
+ threads[0] = std::thread(thread_hammer_and_kill, std::ref(pools));
for (unsigned int worker = 1; worker < HAMMER_MAX_THREADS; worker++)
- {
- if (pthread_create(&threads[worker], &tattr,
- thread_hammer, static_cast<void*>(&weak_pool[worker])))
- std::abort();
- }
+ threads[worker] = std::thread(thread_hammer, std::ref(weak_pool[worker]));
+
// Wait for threads to complete, then check integrity of reference.
- void* status;
- for (unsigned int worker = 0; worker < HAMMER_MAX_THREADS; worker++)
- {
- if (pthread_join(threads[worker], &status))
- std::abort();
- }
+ for (auto& thread : threads)
+ thread.join();
+
obj_pool.clear();
VERIFY( A::counter == 0 );
-
- return 0;
}
int
