From 351dc60c55467552753646c1f585c3fb54cb2b06 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Tue, 6 Nov 2012 09:43:58 -0500 Subject: tile: use atomic op to unlock pthread_spinlock_t Atomic ops are issued directly from the core, rather than potentially sitting in the write buffer, so can improve the performance of other waiters. In addition, if we didn't end up pulling a copy of the cache line where the lock is into cache, by using an atomic op we don't have to acquire the cache line before we can unlock. --- ports/sysdeps/tile/nptl/pthread_spin_unlock.c | 33 +++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 ports/sysdeps/tile/nptl/pthread_spin_unlock.c (limited to 'ports/sysdeps/tile') diff --git a/ports/sysdeps/tile/nptl/pthread_spin_unlock.c b/ports/sysdeps/tile/nptl/pthread_spin_unlock.c new file mode 100644 index 0000000..260f6fa --- /dev/null +++ b/ports/sysdeps/tile/nptl/pthread_spin_unlock.c @@ -0,0 +1,33 @@ +/* pthread_spin_unlock -- unlock a spin lock. Tile version. + Copyright (C) 2012 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 + . */ + +#include "pthreadP.h" +#include + +int +pthread_spin_unlock (pthread_spinlock_t *lock) +{ +#ifdef __tilegx__ + /* Use exchange() to bypass the write buffer. */ + atomic_exchange_rel (lock, 0); +#else + atomic_full_barrier (); + *lock = 0; +#endif + return 0; +} -- cgit v1.1