v1 of this series was originally posted back in September 2017 (see https://gcc.gnu.org/ml/libstdc++/2017-09/msg00083.html )
v2 of this series was originally posted back in January 2018 (see https://gcc.gnu.org/ml/libstdc++/2018-01/msg00035.html ) v3 of this series was originally posted back in August 2018 (see https://gcc.gnu.org/ml/libstdc++/2018-08/msg00001.html ) Changes since v3: * Update libstdc++-v3/config/abi/pre/gnu.ver as recommended by Jonathan Wakely in https://gcc.gnu.org/ml/libstdc++/2018-08/msg00015.html . * Replace _GLIBCXX_DEBUG_ASSERT with __glibcxx_assert in futex.cc as recommended by Jonathan Wakely in https://gcc.gnu.org/ml/libstdc++/2018-08/msg00014.html . * Incorporate extra patch originally posted separately in https://gcc.gnu.org/ml/libstdc++/2018-08/msg00017.html . * Rename incorrect futex_clock_realtime_unavailable to futex_clock_monotonic_unavailable in comment. Spotted by Jonathan Wakely. * Improve commit messages to use GNU two-spaces-after-periods style and add changelogs. * Restrict lines to eighty columns or less. * Remove unnecessarily-added steady_clock_copy from test - slow_clock works just as well. * A few other minor tweaks to tests and comments. Combined ChangeLog entry (generated from the separate messages in each commit): 2019-10-27 Mike Crowe <m...@mcrowe.com> * libstdc++-v3/testsuite/30_threads/async/async.cc (test02): Test steady_clock with std::future::wait_until. (test03): Add new test templated on clock type waiting for future associated with async to resolve. (main): Call test03 to test both system_clock and steady_clock. * libstdc++-v3/src/c++11/futex.cc: Add new constants for required futex flags. Add futex_clock_realtime_unavailable flag to store result of trying to use FUTEX_CLOCK_REALTIME. (__atomic_futex_unsigned_base::_M_futex_wait_until): Try to use FUTEX_WAIT_BITSET with FUTEX_CLOCK_REALTIME and only fall back to using gettimeofday and FUTEX_WAIT if that's not supported. * libstdc++-v3/config/abi/pre/gnu.ver: Update for addition of __atomic_futex_unsigned_base::_M_futex_wait_until_steady. * libstdc++-v3/include/bits/atomic_futex.h (__atomic_futex_unsigned_base): Add comments to clarify that _M_futex_wait_until _M_load_and_test_until use CLOCK_REALTIME. Declare new _M_futex_wait_until_steady and _M_load_and_text_until_steady methods that use CLOCK_MONOTONIC. Add _M_load_and_test_until_impl and _M_load_when_equal_until overloads that accept a steady_clock time_point and use these new methods. * libstdc++-v3/src/c++11/futex.cc: Include headers required for clock_gettime. Add futex_clock_monotonic_flag constant to tell futex to use CLOCK_MONOTONIC to match the existing futex_clock_realtime_flag. Add futex_clock_monotonic_unavailable to store the result of trying to use CLOCK_MONOTONIC. (__atomic_futex_unsigned_base::_M_futex_wait_until_steady): Add new variant of _M_futex_wait_until that uses CLOCK_MONOTONIC to support waiting using steady_clock. * libstdc++-v3/include/bits/atomic_futex.h: (__atomic_futex_unsigned): Change __clock_t typedef to use steady_clock so that unknown clocks are synced to it rather than system_clock. Change existing __clock_t overloads of _M_load_and_text_until_impl and _M_load_when_equal_until to use system_clock explicitly. Remove comment about DR 887 since these changes address that problem as best as we currently able. * libstdc++-v3/include/bits/atomic_futex.h: (__atomic_futex_unsigned) Add loop to _M_load_when_equal_until on generic _Clock to check the timeout against _Clock again after _M_load_when_equal_until returns indicating a timeout. * libstdc++-v3/testsuite/30_threads/async/async.cc: Invent slow_clock that runs at an eleventh of steady_clock's speed. Use it to test the user-supplied-clock variant of __atomic_futex_unsigned::_M_load_when_equal_until works generally with test03 and loops correctly when the timeout time hasn't been reached in test04. * libstdc++-v3/include/bits/atomic_futex.h: (__atomic_futex_unsigned::_M_load_when_equal_for): Round up timeout if required after conversion to reference clock duration. * libstdc++-v3/testsuite/30_threads/async/async.cc: (test_pr68519): New test for the equivalent of PR libstdc++/68519. Mike Crowe (7): libstdc++: Improve async test libstdc++ futex: Use FUTEX_CLOCK_REALTIME for wait libstdc++ futex: Support waiting on std::chrono::steady_clock directly libstdc++ atomic_futex: Use std::chrono::steady_clock as reference clock libstdc++ futex: Loop when waiting against arbitrary clock libstdc++ atomic_futex: Avoid rounding errors in std::future::wait_for libstdc++: Extra async tests, not for merging libstdc++-v3/config/abi/pre/gnu.ver | 10 +- libstdc++-v3/include/bits/atomic_futex.h | 95 +++++++-- libstdc++-v3/src/c++11/futex.cc | 119 +++++++++++- libstdc++-v3/testsuite/30_threads/async/async.cc | 170 ++++++++++++++++- 4 files changed, 379 insertions(+), 15 deletions(-) base-commit: 541ec0fe27585fce2b27750ca2bb1cf8985b043e -- git-series 0.9.1
