From: Thomas Rodgers <rodgert@appliantology.com>
To: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Cc: trodgers@redhat.com, Thomas Rodgers <rodgert@twrodgers.com>
Subject: [PATCH] [libstdc++] Fix test timeout in stop_calback/destroy.cc
Date: Wed, 21 Apr 2021 10:10:22 -0700 [thread overview]
Message-ID: <20210421171022.418139-1-rodgert@appliantology.com> (raw)
From: Thomas Rodgers <rodgert@twrodgers.com>
A change was made to __atomic_semaphore::_S_do_try_acquire() to
(ideally) let the compare_exchange reload the value of __old rather than
always reloading it twice. This causes _M_acquire to spin indefinitely
if the value of __old is already 0.
libstdc++/ChangeLog:
* include/bits/semaphore_base.h: Always reload __old in
__atomic_semaphore::_S_do_try_acquire().
* testsuite/30_threads/stop_token/stop_callback/destroy.cc
re-enable testcase.
---
libstdc++-v3/include/bits/semaphore_base.h | 16 ++++++----------
.../stop_token/stop_callback/destroy.cc | 2 --
2 files changed, 6 insertions(+), 12 deletions(-)
diff --git a/libstdc++-v3/include/bits/semaphore_base.h b/libstdc++-v3/include/bits/semaphore_base.h
index 35469e443b0..84b33423fff 100644
--- a/libstdc++-v3/include/bits/semaphore_base.h
+++ b/libstdc++-v3/include/bits/semaphore_base.h
@@ -196,9 +196,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__atomic_semaphore& operator=(const __atomic_semaphore&) = delete;
static _GLIBCXX_ALWAYS_INLINE bool
- _S_do_try_acquire(__detail::__platform_wait_t* __counter,
- __detail::__platform_wait_t& __old) noexcept
+ _S_do_try_acquire(__detail::__platform_wait_t* __counter) noexcept
{
+ auto __old = __atomic_impl::load(__counter, memory_order::acquire);
if (__old == 0)
return false;
@@ -211,18 +211,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_ALWAYS_INLINE void
_M_acquire() noexcept
{
- auto __old = __atomic_impl::load(&_M_counter, memory_order::acquire);
auto const __pred =
- [this, &__old] { return _S_do_try_acquire(&this->_M_counter, __old); };
+ [this] { return _S_do_try_acquire(&this->_M_counter); };
std::__atomic_wait_address_bare(&_M_counter, __pred);
}
bool
_M_try_acquire() noexcept
{
- auto __old = __atomic_impl::load(&_M_counter, memory_order::acquire);
auto const __pred =
- [this, &__old] { return _S_do_try_acquire(&this->_M_counter, __old); };
+ [this] { return _S_do_try_acquire(&this->_M_counter); };
return std::__detail::__atomic_spin(__pred);
}
@@ -231,9 +229,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_try_acquire_until(const chrono::time_point<_Clock,
_Duration>& __atime) noexcept
{
- auto __old = __atomic_impl::load(&_M_counter, memory_order_relaxed);
auto const __pred =
- [this, &__old] { return _S_do_try_acquire(&this->_M_counter, __old); };
+ [this] { return _S_do_try_acquire(&this->_M_counter); };
return __atomic_wait_address_until_bare(&_M_counter, __pred, __atime);
}
@@ -243,9 +240,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_try_acquire_for(const chrono::duration<_Rep, _Period>& __rtime)
noexcept
{
- auto __old = __atomic_impl::load(&_M_counter, memory_order_relaxed);
auto const __pred =
- [this, &__old] { return _S_do_try_acquire(&this->_M_counter, __old); };
+ [this] { return _S_do_try_acquire(&this->_M_counter); };
return __atomic_wait_address_for_bare(&_M_counter, __pred, __rtime);
}
diff --git a/libstdc++-v3/testsuite/30_threads/stop_token/stop_callback/destroy.cc b/libstdc++-v3/testsuite/30_threads/stop_token/stop_callback/destroy.cc
index c2cfba027cb..061ed448c33 100644
--- a/libstdc++-v3/testsuite/30_threads/stop_token/stop_callback/destroy.cc
+++ b/libstdc++-v3/testsuite/30_threads/stop_token/stop_callback/destroy.cc
@@ -21,8 +21,6 @@
// { dg-require-effective-target pthread }
// { dg-require-gthreads "" }
-// { dg-skip-if "FIXME: times out" { *-*-* } }
-
#include <stop_token>
#include <atomic>
#include <thread>
--
2.30.2
next reply other threads:[~2021-04-21 17:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 17:10 Thomas Rodgers [this message]
2021-04-21 18:23 ` Jonathan Wakely
2021-04-21 20:36 ` Thomas Rodgers
2021-04-21 21:22 ` Jakub Jelinek
2021-04-22 1:34 ` Thomas Rodgers
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