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author | Rogerio Alves <rcardoso@linux.vnet.ibm.com> | 2017-12-05 14:24:14 -0200 |
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committer | Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> | 2017-12-05 17:48:48 -0200 |
commit | 07ed18d26a342741cb25a4739158c65ed9dd4d09 (patch) | |
tree | fb40f10305dcd58b492bf0b685b29b37266bc8c8 /sysdeps | |
parent | a5a2a76bb71940cb8ceb4769a975327027fd55b5 (diff) | |
download | glibc-07ed18d26a342741cb25a4739158c65ed9dd4d09.tar.gz glibc-07ed18d26a342741cb25a4739158c65ed9dd4d09.tar.xz glibc-07ed18d26a342741cb25a4739158c65ed9dd4d09.zip |
Add elision tunables
This patch adds several new tunables to control the behavior of elision on supported platforms[1]. Since elision now depends on tunables, we should always *compile* with elision enabled, and leave the code disabled, but available for runtime selection. This gives us *much* better compile-time testing of the existing code to avoid bit-rot[2]. Tested on ppc, ppc64, ppc64le, s390x and x86_64. [1] This part of the patch was initially proposed by Paul Murphy but was "staled" because the framework have changed since the patch was originally proposed: https://patchwork.sourceware.org/patch/10342/ [2] This part of the patch was inititally proposed as a RFC by Carlos O'Donnell. Make sense to me integrate this on the patch: https://sourceware.org/ml/libc-alpha/2017-05/msg00335.html * elf/dl-tunables.list: Add elision parameters. * manual/tunables.texi: Add entries about elision tunable. * sysdeps/unix/sysv/linux/powerpc/elision-conf.c: Add callback functions to dynamically enable/disable elision. Add multiple callbacks functions to set elision parameters. Deleted __libc_enable_secure check. * sysdeps/unix/sysv/linux/s390/elision-conf.c: Likewise. * sysdeps/unix/sysv/linux/x86/elision-conf.c: Likewise. * configure: Regenerated. * configure.ac: Option enable_lock_elision was deleted. * config.h.in: ENABLE_LOCK_ELISION flag was deleted. * config.make.in: Remove references to enable_lock_elision. * manual/install.texi: Elision configure option was removed. * INSTALL: Regenerated to remove enable_lock_elision. * nptl/Makefile: Disable elision so it can verify error case for destroying a mutex. * sysdeps/powerpc/nptl/elide.h: Cleanup ENABLE_LOCK_ELISION check. Deleted macros for the case when ENABLE_LOCK_ELISION was not defined. * sysdeps/s390/configure: Regenerated. * sysdeps/s390/configure.ac: Remove references to enable_lock_elision.. * nptl/tst-mutex8.c: Deleted all #ifndef ENABLE_LOCK_ELISION from the test. * sysdeps/powerpc/powerpc32/sysdep.h: Deleted all ENABLE_LOCK_ELISION checks. * sysdeps/powerpc/powerpc64/sysdep.h: Likewise. * sysdeps/powerpc/sysdep.h: Likewise. * sysdeps/s390/nptl/bits/pthreadtypes-arch.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/force-elision.h: Likewise. * sysdeps/unix/sysv/linux/s390/elision-conf.h: Likewise. * sysdeps/unix/sysv/linux/s390/force-elision.h: Likewise. * sysdeps/unix/sysv/linux/s390/lowlevellock.h: Likewise. * sysdeps/unix/sysv/linux/s390/Makefile: Remove references to enable-lock-elision. Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/powerpc/nptl/elide.h | 9 | ||||
-rw-r--r-- | sysdeps/powerpc/powerpc32/sysdep.h | 2 | ||||
-rw-r--r-- | sysdeps/powerpc/powerpc64/sysdep.h | 2 | ||||
-rw-r--r-- | sysdeps/powerpc/sysdep.h | 4 | ||||
-rw-r--r-- | sysdeps/s390/configure | 2 | ||||
-rw-r--r-- | sysdeps/s390/configure.ac | 2 | ||||
-rw-r--r-- | sysdeps/s390/nptl/bits/pthreadtypes-arch.h | 4 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/elision-conf.c | 75 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/force-elision.h | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/Makefile | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/elision-conf.c | 72 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/elision-conf.h | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/force-elision.h | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/s390/lowlevellock.h | 2 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/x86/elision-conf.c | 74 |
15 files changed, 209 insertions, 47 deletions
diff --git a/sysdeps/powerpc/nptl/elide.h b/sysdeps/powerpc/nptl/elide.h index 1c42814b71..06986ccbce 100644 --- a/sysdeps/powerpc/nptl/elide.h +++ b/sysdeps/powerpc/nptl/elide.h @@ -19,7 +19,6 @@ #ifndef ELIDE_PPC_H # define ELIDE_PPC_H -#ifdef ENABLE_LOCK_ELISION # include <htm.h> # include <elision-conf.h> @@ -114,12 +113,4 @@ __elide_unlock (int is_lock_free) # define ELIDE_UNLOCK(is_lock_free) \ __elide_unlock (is_lock_free) -# else - -# define ELIDE_LOCK(adapt_count, is_lock_free) 0 -# define ELIDE_TRYLOCK(adapt_count, is_lock_free, write) 0 -# define ELIDE_UNLOCK(is_lock_free) 0 - -#endif /* ENABLE_LOCK_ELISION */ - #endif diff --git a/sysdeps/powerpc/powerpc32/sysdep.h b/sysdeps/powerpc/powerpc32/sysdep.h index 965ea43c94..1d2ff732ee 100644 --- a/sysdeps/powerpc/powerpc32/sysdep.h +++ b/sysdeps/powerpc/powerpc32/sysdep.h @@ -90,7 +90,7 @@ GOT_LABEL: ; \ cfi_endproc; \ ASM_SIZE_DIRECTIVE(name) -#if ! IS_IN(rtld) && defined (ENABLE_LOCK_ELISION) +#if ! IS_IN(rtld) # define ABORT_TRANSACTION \ cmpwi 2,0; \ beq 1f; \ diff --git a/sysdeps/powerpc/powerpc64/sysdep.h b/sysdeps/powerpc/powerpc64/sysdep.h index ab5f395cfd..bff184e374 100644 --- a/sysdeps/powerpc/powerpc64/sysdep.h +++ b/sysdeps/powerpc/powerpc64/sysdep.h @@ -263,7 +263,7 @@ LT_LABELSUFFIX(name,_name_end): ; \ TRACEBACK_MASK(name,mask); \ END_2(name) -#if !IS_IN(rtld) && defined (ENABLE_LOCK_ELISION) +#if !IS_IN(rtld) # define ABORT_TRANSACTION \ cmpdi 13,0; \ beq 1f; \ diff --git a/sysdeps/powerpc/sysdep.h b/sysdeps/powerpc/sysdep.h index f07b959eee..d1a9bd9b55 100644 --- a/sysdeps/powerpc/sysdep.h +++ b/sysdeps/powerpc/sysdep.h @@ -21,10 +21,8 @@ */ #define _SYSDEPS_SYSDEP_H 1 #include <bits/hwcap.h> -#ifdef ENABLE_LOCK_ELISION #include <tls.h> #include <htm.h> -#endif #define PPC_FEATURE_970 (PPC_FEATURE_POWER4 + PPC_FEATURE_HAS_ALTIVEC) @@ -176,7 +174,7 @@ we abort transaction just before syscalls. [1] Documentation/powerpc/transactional_memory.txt [Syscalls] */ -#if !IS_IN(rtld) && defined (ENABLE_LOCK_ELISION) +#if !IS_IN(rtld) # define ABORT_TRANSACTION \ ({ \ if (THREAD_GET_TM_CAPABLE ()) \ diff --git a/sysdeps/s390/configure b/sysdeps/s390/configure index d4a4a3dcf8..74b415f2ab 100644 --- a/sysdeps/s390/configure +++ b/sysdeps/s390/configure @@ -35,7 +35,7 @@ fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_gcc_builtin_tbegin" >&5 $as_echo "$libc_cv_gcc_builtin_tbegin" >&6; } -if test "$enable_lock_elision" = yes && test "$libc_cv_gcc_builtin_tbegin" = no ; then +if test "$libc_cv_gcc_builtin_tbegin" = no ; then critic_missing="$critic_missing The used GCC has no support for __builtin_tbegin, which is needed for lock-elision on target S390." fi diff --git a/sysdeps/s390/configure.ac b/sysdeps/s390/configure.ac index 7d0b5ce46f..1cdb021282 100644 --- a/sysdeps/s390/configure.ac +++ b/sysdeps/s390/configure.ac @@ -26,7 +26,7 @@ else fi rm -f conftest* ]) -if test "$enable_lock_elision" = yes && test "$libc_cv_gcc_builtin_tbegin" = no ; then +if test "$libc_cv_gcc_builtin_tbegin" = no ; then critic_missing="$critic_missing The used GCC has no support for __builtin_tbegin, which is needed for lock-elision on target S390." fi diff --git a/sysdeps/s390/nptl/bits/pthreadtypes-arch.h b/sysdeps/s390/nptl/bits/pthreadtypes-arch.h index 1ae277367d..fd15931974 100644 --- a/sysdeps/s390/nptl/bits/pthreadtypes-arch.h +++ b/sysdeps/s390/nptl/bits/pthreadtypes-arch.h @@ -40,11 +40,7 @@ /* Definitions for internal mutex struct. */ #define __PTHREAD_COMPAT_PADDING_MID #define __PTHREAD_COMPAT_PADDING_END -#ifdef ENABLE_LOCK_ELISION #define __PTHREAD_MUTEX_LOCK_ELISION 1 -#else -#define __PTHREAD_MUTEX_LOCK_ELISION 0 -#endif #define __PTHREAD_MUTEX_NUSERS_AFTER_KIND (__WORDSIZE != 64) #define __PTHREAD_MUTEX_USE_UNION (__WORDSIZE != 64) diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-conf.c b/sysdeps/unix/sysv/linux/powerpc/elision-conf.c index f631f0a035..06361e6b2f 100644 --- a/sysdeps/unix/sysv/linux/powerpc/elision-conf.c +++ b/sysdeps/unix/sysv/linux/powerpc/elision-conf.c @@ -22,6 +22,11 @@ #include <unistd.h> #include <dl-procinfo.h> +#if HAVE_TUNABLES +# define TUNABLE_NAMESPACE elision +#endif +#include <elf/dl-tunables.h> + /* Reasonable initial tuning values, may be revised in the future. This is a conservative initial value. */ @@ -50,7 +55,52 @@ struct elision_config __elision_aconf = DEFAULT locks should be automatically use elision in pthread_mutex_lock(). Disabled for suid programs. Only used when elision is available. */ -int __pthread_force_elision attribute_hidden; +int __pthread_force_elision attribute_hidden = 0; + +#if HAVE_TUNABLES +static inline void +__always_inline +do_set_elision_enable (int32_t elision_enable) +{ + /* Enable elision if it's avaliable 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 = (GLRO (dl_hwcap2) + & PPC_FEATURE2_HAS_HTM) ? 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 inline void \ +__always_inline \ +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 (skip_lock_out_of_tbegin_retries, int32_t); +TUNABLE_CALLBACK_FNDECL (try_tbegin, int32_t); +TUNABLE_CALLBACK_FNDECL (skip_trylock_internal_abort, int32_t); +#endif /* Initialize elision. */ @@ -59,13 +109,26 @@ elision_init (int argc __attribute__ ((unused)), char **argv __attribute__ ((unused)), char **environ) { -#ifdef ENABLE_LOCK_ELISION - int elision_available = (GLRO (dl_hwcap2) & PPC_FEATURE2_HAS_HTM) ? 1 : 0; - __pthread_force_elision = __libc_enable_secure ? 0 : elision_available; +#if HAVE_TUNABLES + /* 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 (skip_lock_after_retries, int32_t, + TUNABLE_CALLBACK (set_elision_skip_lock_out_of_tbegin_retries)); + TUNABLE_GET (tries, int32_t, + TUNABLE_CALLBACK (set_elision_try_tbegin)); + TUNABLE_GET (skip_trylock_internal_abort, int32_t, + TUNABLE_CALLBACK (set_elision_skip_trylock_internal_abort)); #endif + if (!__pthread_force_elision) - /* Disable elision on rwlocks. */ - __elision_aconf.try_tbegin = 0; + __elision_aconf.try_tbegin = 0; /* Disable elision on rwlocks. */ } #ifdef SHARED diff --git a/sysdeps/unix/sysv/linux/powerpc/force-elision.h b/sysdeps/unix/sysv/linux/powerpc/force-elision.h index 318f7915c7..d1feeeb01e 100644 --- a/sysdeps/unix/sysv/linux/powerpc/force-elision.h +++ b/sysdeps/unix/sysv/linux/powerpc/force-elision.h @@ -16,7 +16,6 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#ifdef ENABLE_LOCK_ELISION /* Automatically enable elision for existing user lock kinds. */ #define FORCE_ELISION(m, s) \ if (__pthread_force_elision \ @@ -25,4 +24,3 @@ mutex->__data.__kind |= PTHREAD_MUTEX_ELISION_NP; \ s; \ } -#endif diff --git a/sysdeps/unix/sysv/linux/s390/Makefile b/sysdeps/unix/sysv/linux/s390/Makefile index c5f544d139..77f38523b5 100644 --- a/sysdeps/unix/sysv/linux/s390/Makefile +++ b/sysdeps/unix/sysv/linux/s390/Makefile @@ -16,7 +16,6 @@ sysdep_routines += dl-vdso endif ifeq ($(subdir),nptl) -ifeq ($(enable-lock-elision),yes) libpthread-sysdep_routines += elision-lock elision-unlock elision-timed \ elision-trylock @@ -26,7 +25,6 @@ CFLAGS-elision-timed.c = $(elision-CFLAGS) CFLAGS-elision-trylock.c = $(elision-CFLAGS) CFLAGS-elision-unlock.c = $(elision-CFLAGS) endif -endif ifeq ($(subdir),misc) tests += tst-ptrace-singleblock diff --git a/sysdeps/unix/sysv/linux/s390/elision-conf.c b/sysdeps/unix/sysv/linux/s390/elision-conf.c index cc0fdef2aa..ab334cb79b 100644 --- a/sysdeps/unix/sysv/linux/s390/elision-conf.c +++ b/sysdeps/unix/sysv/linux/s390/elision-conf.c @@ -22,6 +22,11 @@ #include <unistd.h> #include <dl-procinfo.h> +#if HAVE_TUNABLES +# define TUNABLE_NAMESPACE elision +#endif +#include <elf/dl-tunables.h> + /* Reasonable initial tuning values, may be revised in the future. This is a conservative initial value. */ @@ -53,6 +58,50 @@ struct elision_config __elision_aconf = int __pthread_force_elision attribute_hidden = 0; +#if HAVE_TUNABLES +static inline void +__always_inline +do_set_elision_enable (int32_t elision_enable) +{ + /* Enable elision if it's avaliable 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 = (GLRO (dl_hwcap) & HWCAP_S390_TE) ? 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 inline void \ +__always_inline \ +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 (skip_lock_out_of_tbegin_retries, int32_t); +TUNABLE_CALLBACK_FNDECL (try_tbegin, int32_t); +TUNABLE_CALLBACK_FNDECL (skip_trylock_internal_abort, int32_t); +#endif + /* Initialize elison. */ static void @@ -60,11 +109,26 @@ elision_init (int argc __attribute__ ((unused)), char **argv __attribute__ ((unused)), char **environ) { - /* Set when the CPU and the kernel supports transactional execution. - When false elision is never attempted. */ - int elision_available = (GLRO (dl_hwcap) & HWCAP_S390_TE) ? 1 : 0; +#if HAVE_TUNABLES + /* 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 (skip_lock_after_retries, int32_t, + TUNABLE_CALLBACK (set_elision_skip_lock_out_of_tbegin_retries)); + TUNABLE_GET (tries, int32_t, + TUNABLE_CALLBACK (set_elision_try_tbegin)); + TUNABLE_GET (skip_trylock_internal_abort, int32_t, + TUNABLE_CALLBACK (set_elision_skip_trylock_internal_abort)); +#endif - __pthread_force_elision = __libc_enable_secure ? 0 : elision_available; + if (!__pthread_force_elision) + __elision_aconf.try_tbegin = 0; /* Disable elision on rwlocks. */ } #ifdef SHARED diff --git a/sysdeps/unix/sysv/linux/s390/elision-conf.h b/sysdeps/unix/sysv/linux/s390/elision-conf.h index 3143f3b114..32f0ed3b8c 100644 --- a/sysdeps/unix/sysv/linux/s390/elision-conf.h +++ b/sysdeps/unix/sysv/linux/s390/elision-conf.h @@ -15,7 +15,6 @@ You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#ifdef ENABLE_LOCK_ELISION #ifndef _ELISION_CONF_H #define _ELISION_CONF_H 1 @@ -41,4 +40,3 @@ extern int __pthread_force_elision attribute_hidden; #define HAVE_ELISION 1 #endif -#endif diff --git a/sysdeps/unix/sysv/linux/s390/force-elision.h b/sysdeps/unix/sysv/linux/s390/force-elision.h index 3ae3bcd566..8e1e33e1c5 100644 --- a/sysdeps/unix/sysv/linux/s390/force-elision.h +++ b/sysdeps/unix/sysv/linux/s390/force-elision.h @@ -16,7 +16,6 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#ifdef ENABLE_LOCK_ELISION /* Automatically enable elision for existing user lock kinds. */ #define FORCE_ELISION(m, s) \ if (__pthread_force_elision \ @@ -25,4 +24,3 @@ mutex->__data.__kind |= PTHREAD_MUTEX_ELISION_NP; \ s; \ } -#endif diff --git a/sysdeps/unix/sysv/linux/s390/lowlevellock.h b/sysdeps/unix/sysv/linux/s390/lowlevellock.h index 604137f7f2..48f87a85f5 100644 --- a/sysdeps/unix/sysv/linux/s390/lowlevellock.h +++ b/sysdeps/unix/sysv/linux/s390/lowlevellock.h @@ -22,7 +22,6 @@ #include <sysdeps/nptl/lowlevellock.h> /* Transactional lock elision definitions. */ -# ifdef ENABLE_LOCK_ELISION extern int __lll_timedlock_elision (int *futex, short *adapt_count, const struct timespec *timeout, int private) attribute_hidden; @@ -45,6 +44,5 @@ extern int __lll_trylock_elision(int *futex, short *adapt_count) __lll_unlock_elision (&(futex), &(adapt_count), private) # define lll_trylock_elision(futex, adapt_count) \ __lll_trylock_elision(&(futex), &(adapt_count)) -# endif /* ENABLE_LOCK_ELISION */ #endif /* lowlevellock.h */ diff --git a/sysdeps/unix/sysv/linux/x86/elision-conf.c b/sysdeps/unix/sysv/linux/x86/elision-conf.c index 673b0005a7..7e9fbf9382 100644 --- a/sysdeps/unix/sysv/linux/x86/elision-conf.c +++ b/sysdeps/unix/sysv/linux/x86/elision-conf.c @@ -22,6 +22,11 @@ #include <elision-conf.h> #include <unistd.h> +#if HAVE_TUNABLES +# define TUNABLE_NAMESPACE elision +#endif +#include <elf/dl-tunables.h> + /* Reasonable initial tuning values, may be revised in the future. This is a conservative initial value. */ @@ -48,21 +53,76 @@ struct elision_config __elision_aconf = pthread_mutex_lock(). Disabled for suid programs. Only used when elision is available. */ -int __pthread_force_elision attribute_hidden; +int __pthread_force_elision attribute_hidden = 0; + +#if HAVE_TUNABLES +static inline void +__always_inline +do_set_elision_enable (int32_t elision_enable) +{ + /* Enable elision if it's avaliable 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 = HAS_CPU_FEATURE (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. */ -/* Initialize elison. */ +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 inline void \ +__always_inline \ +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); +#endif + +/* Initialize elision. */ static void elision_init (int argc __attribute__ ((unused)), char **argv __attribute__ ((unused)), char **environ) { - int elision_available = HAS_CPU_FEATURE (RTM); -#ifdef ENABLE_LOCK_ELISION - __pthread_force_elision = __libc_enable_secure ? 0 : elision_available; +#if HAVE_TUNABLES + /* 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)); #endif - if (!elision_available) - __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks */ + + if (!__pthread_force_elision) + __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks. */ } #ifdef SHARED |