diff options
| -rw-r--r-- | ChangeLog | 3 | ||||
| -rw-r--r-- | nptl/lowlevellock.c | 31 |
2 files changed, 22 insertions, 12 deletions
diff --git a/ChangeLog b/ChangeLog index f523a6c08e..6a26dad64f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,8 @@ 2019-05-14 Adhemerval Zanella <adhemerval.zanella@linaro.org> + * nptl/lowlevellock.c (__lll_lock_wait, __lll_lock_wait_private): + Optimize futex call and add systemtap probe. + * nptl/pthreadP.h (CANCEL_ASYNC, CANCEL_RESET, LIBC_CANCEL_ASYNC, LIBC_CANCEL_RESET, __libc_enable_asynccancel, __libc_disable_asynccancel, __librt_enable_asynccancel, diff --git a/nptl/lowlevellock.c b/nptl/lowlevellock.c index 5eaa3807ea..47548ff121 100644 --- a/nptl/lowlevellock.c +++ b/nptl/lowlevellock.c @@ -17,20 +17,23 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#include <errno.h> #include <sysdep.h> #include <lowlevellock.h> -#include <sys/time.h> #include <atomic.h> +#include <stap-probe.h> void __lll_lock_wait_private (int *futex) { - if (*futex == 2) - lll_futex_wait (futex, 2, LLL_PRIVATE); /* Wait if *futex == 2. */ - - while (atomic_exchange_acq (futex, 2) != 0) - lll_futex_wait (futex, 2, LLL_PRIVATE); /* Wait if *futex == 2. */ + if (atomic_load_relaxed (futex) == 2) + goto futex; + + while (atomic_exchange_acquire (futex, 2) != 0) + { + futex: + LIBC_PROBE (lll_lock_wait_private, 1, futex); + lll_futex_wait (futex, 2, LLL_PRIVATE); /* Wait if *futex == 2. */ + } } @@ -39,10 +42,14 @@ __lll_lock_wait_private (int *futex) void __lll_lock_wait (int *futex, int private) { - if (*futex == 2) - lll_futex_wait (futex, 2, private); /* Wait if *futex == 2. */ - - while (atomic_exchange_acq (futex, 2) != 0) - lll_futex_wait (futex, 2, private); /* Wait if *futex == 2. */ + if (atomic_load_relaxed (futex) == 2) + goto futex; + + while (atomic_exchange_acquire (futex, 2) != 0) + { + futex: + LIBC_PROBE (lll_lock_wait, 1, futex); + lll_futex_wait (futex, 2, private); /* Wait if *futex == 2. */ + } } #endif |