diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86/elision-conf.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86/elision-conf.c | 109 |
1 files changed, 0 insertions, 109 deletions
diff --git a/sysdeps/unix/sysv/linux/x86/elision-conf.c b/sysdeps/unix/sysv/linux/x86/elision-conf.c deleted file mode 100644 index cf120a9ec6..0000000000 --- a/sysdeps/unix/sysv/linux/x86/elision-conf.c +++ /dev/null @@ -1,109 +0,0 @@ -/* elision-conf.c: Lock elision tunable parameters. - Copyright (C) 2013-2025 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 - <https://www.gnu.org/licenses/>. */ - -#include "config.h" -#include <pthreadP.h> -#include <init-arch.h> -#include <elision-conf.h> -#include <unistd.h> - -#define TUNABLE_NAMESPACE elision -#include <elf/dl-tunables.h> - -/* Reasonable initial tuning values, may be revised in the future. - This is a conservative initial value. */ - -struct elision_config __elision_aconf = - { - /* How often to not attempt to use elision if a transaction aborted - because the lock is already acquired. Expressed in number of lock - acquisition attempts. */ - .skip_lock_busy = 3, - /* How often to not attempt to use elision if a transaction aborted due - to reasons other than other threads' memory accesses. Expressed in - number of lock acquisition attempts. */ - .skip_lock_internal_abort = 3, - /* How often we retry using elision if there is chance for the transaction - to finish execution (e.g., it wasn't aborted due to the lock being - already acquired. */ - .retry_try_xbegin = 3, - /* Same as SKIP_LOCK_INTERNAL_ABORT but for trylock. */ - .skip_trylock_internal_abort = 3, - }; - -static __always_inline void -do_set_elision_enable (int32_t elision_enable) -{ - /* Enable elision if it's available in hardware. It's not necessary to check - if __libc_enable_secure isn't enabled since elision_enable will be set - according to the default, which is disabled. */ - if (elision_enable == 1) - __pthread_force_elision = CPU_FEATURE_USABLE (RTM) ? 1 : 0; -} - -/* The pthread->elision_enable tunable is 0 or 1 indicating that elision - should be disabled or enabled respectively. The feature will only be used - if it's supported by the hardware. */ - -void -TUNABLE_CALLBACK (set_elision_enable) (tunable_val_t *valp) -{ - int32_t elision_enable = (int32_t) valp->numval; - do_set_elision_enable (elision_enable); -} - -#define TUNABLE_CALLBACK_FNDECL(__name, __type) \ -static __always_inline void \ -do_set_elision_ ## __name (__type value) \ -{ \ - __elision_aconf.__name = value; \ -} \ -void \ -TUNABLE_CALLBACK (set_elision_ ## __name) (tunable_val_t *valp) \ -{ \ - __type value = (__type) (valp)->numval; \ - do_set_elision_ ## __name (value); \ -} - -TUNABLE_CALLBACK_FNDECL (skip_lock_busy, int32_t); -TUNABLE_CALLBACK_FNDECL (skip_lock_internal_abort, int32_t); -TUNABLE_CALLBACK_FNDECL (retry_try_xbegin, int32_t); -TUNABLE_CALLBACK_FNDECL (skip_trylock_internal_abort, int32_t); - -/* Initialize elision. */ - -void -__lll_elision_init (void) -{ - /* Elision depends on tunables and must be explicitly turned on by setting - the appropriate tunable on a supported platform. */ - - TUNABLE_GET (enable, int32_t, - TUNABLE_CALLBACK (set_elision_enable)); - TUNABLE_GET (skip_lock_busy, int32_t, - TUNABLE_CALLBACK (set_elision_skip_lock_busy)); - TUNABLE_GET (skip_lock_internal_abort, int32_t, - TUNABLE_CALLBACK (set_elision_skip_lock_internal_abort)); - TUNABLE_GET (tries, int32_t, - TUNABLE_CALLBACK (set_elision_retry_try_xbegin)); - TUNABLE_GET (skip_trylock_internal_abort, int32_t, - TUNABLE_CALLBACK (set_elision_skip_trylock_internal_abort)); - - if (!__pthread_force_elision) - __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks. */ -} |