|
|
ce426f |
In RHEL7 we already have the newer cpu-feature support so we need
|
|
|
ce426f |
to backport b376899d2 to get 1cdbe5794 to compile. The goal wtih elision
|
|
|
ce426f |
is an incremental set of patches each which compile and introduce the
|
|
|
ce426f |
required functionality for elision.
|
|
|
ce426f |
|
|
|
ce426f |
Partial backport of:
|
|
|
ce426f |
|
|
|
ce426f |
commit b376899d27e5ac892f0339cf1bbb3d2158347db8
|
|
|
ce426f |
Author: H.J. Lu <hjl.tools@gmail.com>
|
|
|
ce426f |
Date: Thu Aug 13 03:40:40 2015 -0700
|
|
|
ce426f |
|
|
|
ce426f |
Update x86 elision-conf.c for <cpu-features.h>
|
|
|
ce426f |
|
|
|
ce426f |
This patch updates x86 elision-conf.c to use the newly defined
|
|
|
ce426f |
HAS_CPU_FEATURE from <cpu-features.h>.
|
|
|
ce426f |
|
|
|
ce426f |
* sysdeps/unix/sysv/linux/x86/elision-conf.c (elision_init):
|
|
|
ce426f |
Replace HAS_RTM with HAS_CPU_FEATURE (RTM).
|
|
|
ce426f |
|
|
|
ce426f |
|
|
|
ce426f |
Full backport of:
|
|
|
ce426f |
|
|
|
ce426f |
commit 1717da59aed9612becd56aaa1249aac695af4c8a
|
|
|
ce426f |
Author: Andi Kleen <ak@linux.intel.com>
|
|
|
ce426f |
Date: Thu May 16 19:17:14 2013 -0700
|
|
|
ce426f |
|
|
|
ce426f |
Add a configure option to enable lock elision and disable by default
|
|
|
ce426f |
|
|
|
ce426f |
Can be enabled with --enable-lock-elision=yes at configure time.
|
|
|
ce426f |
|
|
|
ce426f |
commit 1cdbe579482c07e9f4bb3baa4864da2d3e7eb837
|
|
|
ce426f |
Author: Andi Kleen <ak@linux.intel.com>
|
|
|
ce426f |
Date: Sat Nov 10 00:51:26 2012 -0800
|
|
|
ce426f |
|
|
|
ce426f |
Add the low level infrastructure for pthreads lock elision with TSX
|
|
|
ce426f |
|
|
|
ce426f |
Lock elision using TSX is a technique to optimize lock scaling
|
|
|
ce426f |
It allows to run locks in parallel using hardware support for
|
|
|
ce426f |
a transactional execution mode in 4th generation Intel Core CPUs.
|
|
|
ce426f |
See http://www.intel.com/software/tsx for more Information.
|
|
|
ce426f |
|
|
|
ce426f |
This patch implements a simple adaptive lock elision algorithm based
|
|
|
ce426f |
on RTM. It enables elision for the pthread mutexes and rwlocks.
|
|
|
ce426f |
The algorithm keeps track whether a mutex successfully elides or not,
|
|
|
ce426f |
and stops eliding for some time when it is not.
|
|
|
ce426f |
|
|
|
ce426f |
When the CPU supports RTM the elision path is automatically tried,
|
|
|
ce426f |
otherwise any elision is disabled.
|
|
|
ce426f |
|
|
|
ce426f |
The adaptation algorithm and its tuning is currently preliminary.
|
|
|
ce426f |
|
|
|
ce426f |
The code adds some checks to the lock fast paths. Micro-benchmarks
|
|
|
ce426f |
show little to no difference without RTM.
|
|
|
ce426f |
|
|
|
ce426f |
This patch implements the low level "lll_" code for lock elision.
|
|
|
ce426f |
Followon patches hook this into the pthread implementation
|
|
|
ce426f |
|
|
|
ce426f |
Changes with the RTM mutexes:
|
|
|
ce426f |
-----------------------------
|
|
|
ce426f |
Lock elision in pthreads is generally compatible with existing programs.
|
|
|
ce426f |
There are some obscure exceptions, which are expected to be uncommon.
|
|
|
ce426f |
See the manual for more details.
|
|
|
ce426f |
|
|
|
ce426f |
- A broken program that unlocks a free lock will crash.
|
|
|
ce426f |
There are ways around this with some tradeoffs (more code in hot paths)
|
|
|
ce426f |
I'm still undecided on what approach to take here; have to wait for testing reports.
|
|
|
ce426f |
- pthread_mutex_destroy of a lock mutex will not return EBUSY but 0.
|
|
|
ce426f |
- There's also a similar situation with trylock outside the mutex,
|
|
|
ce426f |
"knowing" that the mutex must be held due to some other condition.
|
|
|
ce426f |
In this case an assert failure cannot be recovered. This situation is
|
|
|
ce426f |
usually an existing bug in the program.
|
|
|
ce426f |
- Same applies to the rwlocks. Some of the return values changes
|
|
|
ce426f |
(for example there is no EDEADLK for an elided lock, unless it aborts.
|
|
|
ce426f |
However when elided it will also never deadlock of course)
|
|
|
ce426f |
- Timing changes, so broken programs that make assumptions about specific timing
|
|
|
ce426f |
may expose already existing latent problems. Note that these broken programs will
|
|
|
ce426f |
break in other situations too (loaded system, new faster hardware, compiler
|
|
|
ce426f |
optimizations etc.)
|
|
|
ce426f |
- Programs with non recursive mutexes that take them recursively in a thread and
|
|
|
ce426f |
which would always deadlock without elision may not always see a deadlock.
|
|
|
ce426f |
The deadlock will only happen on an early or delayed abort (which typically
|
|
|
ce426f |
happens at some point)
|
|
|
ce426f |
This only happens for mutexes not explicitely set to PTHREAD_MUTEX_NORMAL
|
|
|
ce426f |
or PTHREAD_MUTEX_ADAPTIVE_NP. PTHREAD_MUTEX_NORMAL mutexes do not elide.
|
|
|
ce426f |
|
|
|
ce426f |
The elision default can be set at configure time.
|
|
|
ce426f |
|
|
|
ce426f |
This patch implements the basic infrastructure for elision.
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/elision-conf.h
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/elision-conf.h
|
|
|
ce426f |
@@ -0,0 +1 @@
|
|
|
ce426f |
+/* empty */
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/i386/lowlevellock.h
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/nptl/sysdeps/unix/sysv/linux/i386/lowlevellock.h
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/i386/lowlevellock.h
|
|
|
ce426f |
@@ -430,6 +430,12 @@ LLL_STUB_UNWIND_INFO_END
|
|
|
ce426f |
: "memory"); \
|
|
|
ce426f |
result; })
|
|
|
ce426f |
|
|
|
ce426f |
+extern int __lll_timedlock_elision (int *futex, short *adapt_count,
|
|
|
ce426f |
+ const struct timespec *timeout,
|
|
|
ce426f |
+ int private) attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define lll_timedlock_elision(futex, adapt_count, timeout, private) \
|
|
|
ce426f |
+ __lll_timedlock_elision(&(futex), &(adapt_count), timeout, private)
|
|
|
ce426f |
|
|
|
ce426f |
#define lll_robust_timedlock(futex, timeout, id, private) \
|
|
|
ce426f |
({ int result, ignore1, ignore2, ignore3; \
|
|
|
ce426f |
@@ -583,6 +589,22 @@ extern int __lll_timedwait_tid (int *tid
|
|
|
ce426f |
} \
|
|
|
ce426f |
__result; })
|
|
|
ce426f |
|
|
|
ce426f |
+extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
|
|
|
ce426f |
+ attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+extern int __lll_unlock_elision(int *lock, int private)
|
|
|
ce426f |
+ attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+extern int __lll_trylock_elision(int *lock, short *adapt_count)
|
|
|
ce426f |
+ attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define lll_lock_elision(futex, adapt_count, private) \
|
|
|
ce426f |
+ __lll_lock_elision (&(futex), &(adapt_count), private)
|
|
|
ce426f |
+#define lll_unlock_elision(futex, private) \
|
|
|
ce426f |
+ __lll_unlock_elision (&(futex), private)
|
|
|
ce426f |
+#define lll_trylock_elision(futex, adapt_count) \
|
|
|
ce426f |
+ __lll_trylock_elision(&(futex), &(adapt_count))
|
|
|
ce426f |
+
|
|
|
ce426f |
#endif /* !__ASSEMBLER__ */
|
|
|
ce426f |
|
|
|
ce426f |
#endif /* lowlevellock.h */
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/Makefile
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/Makefile
|
|
|
ce426f |
@@ -0,0 +1,2 @@
|
|
|
ce426f |
+libpthread-sysdep_routines += elision-lock elision-unlock elision-timed \
|
|
|
ce426f |
+ elision-trylock
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-conf.c
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-conf.c
|
|
|
ce426f |
@@ -0,0 +1,90 @@
|
|
|
ce426f |
+/* elision-conf.c: Lock elision tunable parameters.
|
|
|
ce426f |
+ Copyright (C) 2013 Free Software Foundation, Inc.
|
|
|
ce426f |
+ This file is part of the GNU C Library.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
ce426f |
+ modify it under the terms of the GNU Lesser General Public
|
|
|
ce426f |
+ License as published by the Free Software Foundation; either
|
|
|
ce426f |
+ version 2.1 of the License, or (at your option) any later version.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
ce426f |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
ce426f |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
ce426f |
+ Lesser General Public License for more details.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
ce426f |
+ License along with the GNU C Library; if not, see
|
|
|
ce426f |
+ <http://www.gnu.org/licenses/>. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+#include "config.h"
|
|
|
ce426f |
+#include <pthreadP.h>
|
|
|
ce426f |
+#include <init-arch.h>
|
|
|
ce426f |
+#include <elision-conf.h>
|
|
|
ce426f |
+#include <unistd.h>
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Reasonable initial tuning values, may be revised in the future.
|
|
|
ce426f |
+ This is a conservative initial value. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+struct elision_config __elision_aconf =
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ /* How often to not attempt to use elision if a transaction aborted
|
|
|
ce426f |
+ because the lock is already acquired. Expressed in number of lock
|
|
|
ce426f |
+ acquisition attempts. */
|
|
|
ce426f |
+ .skip_lock_busy = 3,
|
|
|
ce426f |
+ /* How often to not attempt to use elision if a transaction aborted due
|
|
|
ce426f |
+ to reasons other than other threads' memory accesses. Expressed in
|
|
|
ce426f |
+ number of lock acquisition attempts. */
|
|
|
ce426f |
+ .skip_lock_internal_abort = 3,
|
|
|
ce426f |
+ /* How often we retry using elision if there is chance for the transaction
|
|
|
ce426f |
+ to finish execution (e.g., it wasn't aborted due to the lock being
|
|
|
ce426f |
+ already acquired. */
|
|
|
ce426f |
+ .retry_try_xbegin = 3,
|
|
|
ce426f |
+ /* Same as SKIP_LOCK_INTERNAL_ABORT but for trylock. */
|
|
|
ce426f |
+ .skip_trylock_internal_abort = 3,
|
|
|
ce426f |
+ };
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Elided rwlock toggle, set when elision is available and is
|
|
|
ce426f |
+ enabled for rwlocks. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+int __rwlock_rtm_enabled attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Retries for elided rwlocks on read. Conservative initial value. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+int __rwlock_rtm_read_retries attribute_hidden = 3;
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Set when the CPU supports elision. When false elision is never attempted. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+int __elision_available attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Force elision for all new locks. This is used to decide whether existing
|
|
|
ce426f |
+ DEFAULT locks should be automatically upgraded to elision in
|
|
|
ce426f |
+ pthread_mutex_lock(). Disabled for suid programs. Only used when elision
|
|
|
ce426f |
+ is available. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+int __pthread_force_elision attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Initialize elison. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+static void
|
|
|
ce426f |
+elision_init (int argc __attribute__ ((unused)),
|
|
|
ce426f |
+ char **argv __attribute__ ((unused)),
|
|
|
ce426f |
+ char **environ)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ __elision_available = HAS_CPU_FEATURE (RTM);
|
|
|
ce426f |
+#ifdef ENABLE_LOCK_ELISION
|
|
|
ce426f |
+ __pthread_force_elision = __libc_enable_secure ? 0 : __elision_available;
|
|
|
ce426f |
+ __rwlock_rtm_enabled = __libc_enable_secure ? 0 : __elision_available;
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
+}
|
|
|
ce426f |
+
|
|
|
ce426f |
+#ifdef SHARED
|
|
|
ce426f |
+# define INIT_SECTION ".init_array"
|
|
|
ce426f |
+#else
|
|
|
ce426f |
+# define INIT_SECTION ".preinit_array"
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
+
|
|
|
ce426f |
+void (*const __pthread_init_array []) (int, char **, char **)
|
|
|
ce426f |
+ __attribute__ ((section (INIT_SECTION), aligned (sizeof (void *)))) =
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ &elision_init
|
|
|
ce426f |
+};
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-conf.h
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-conf.h
|
|
|
ce426f |
@@ -0,0 +1,44 @@
|
|
|
ce426f |
+/* elision-conf.h: Lock elision tunable parameters.
|
|
|
ce426f |
+ Copyright (C) 2013 Free Software Foundation, Inc.
|
|
|
ce426f |
+ This file is part of the GNU C Library.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
ce426f |
+ modify it under the terms of the GNU Lesser General Public
|
|
|
ce426f |
+ License as published by the Free Software Foundation; either
|
|
|
ce426f |
+ version 2.1 of the License, or (at your option) any later version.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
ce426f |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
ce426f |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
ce426f |
+ Lesser General Public License for more details.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
ce426f |
+ License along with the GNU C Library; if not, see
|
|
|
ce426f |
+ <http://www.gnu.org/licenses/>. */
|
|
|
ce426f |
+#ifndef _ELISION_CONF_H
|
|
|
ce426f |
+#define _ELISION_CONF_H 1
|
|
|
ce426f |
+
|
|
|
ce426f |
+#include <pthread.h>
|
|
|
ce426f |
+#include <cpuid.h>
|
|
|
ce426f |
+#include <time.h>
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Should make sure there is no false sharing on this. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+struct elision_config
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ int skip_lock_busy;
|
|
|
ce426f |
+ int skip_lock_internal_abort;
|
|
|
ce426f |
+ int retry_try_xbegin;
|
|
|
ce426f |
+ int skip_trylock_internal_abort;
|
|
|
ce426f |
+};
|
|
|
ce426f |
+
|
|
|
ce426f |
+extern struct elision_config __elision_aconf attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+extern int __rwlock_rtm_enabled attribute_hidden;
|
|
|
ce426f |
+extern int __elision_available attribute_hidden;
|
|
|
ce426f |
+extern int __pthread_force_elision attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Tell the test suite to test elision for this architecture. */
|
|
|
ce426f |
+#define HAVE_ELISION 1
|
|
|
ce426f |
+
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-lock.c
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-lock.c
|
|
|
ce426f |
@@ -0,0 +1,95 @@
|
|
|
ce426f |
+/* elision-lock.c: Elided pthread mutex lock.
|
|
|
ce426f |
+ Copyright (C) 2011-2013 Free Software Foundation, Inc.
|
|
|
ce426f |
+ This file is part of the GNU C Library.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
ce426f |
+ modify it under the terms of the GNU Lesser General Public
|
|
|
ce426f |
+ License as published by the Free Software Foundation; either
|
|
|
ce426f |
+ version 2.1 of the License, or (at your option) any later version.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
ce426f |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
ce426f |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
ce426f |
+ Lesser General Public License for more details.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
ce426f |
+ License along with the GNU C Library; if not, see
|
|
|
ce426f |
+ <http://www.gnu.org/licenses/>. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+#include <pthread.h>
|
|
|
ce426f |
+#include "pthreadP.h"
|
|
|
ce426f |
+#include "lowlevellock.h"
|
|
|
ce426f |
+#include "hle.h"
|
|
|
ce426f |
+#include <elision-conf.h>
|
|
|
ce426f |
+
|
|
|
ce426f |
+#if !defined(LLL_LOCK) && !defined(EXTRAARG)
|
|
|
ce426f |
+/* Make sure the configuration code is always linked in for static
|
|
|
ce426f |
+ libraries. */
|
|
|
ce426f |
+#include "elision-conf.c"
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
+
|
|
|
ce426f |
+#ifndef EXTRAARG
|
|
|
ce426f |
+#define EXTRAARG
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
+#ifndef LLL_LOCK
|
|
|
ce426f |
+#define LLL_LOCK(a,b) lll_lock(a,b), 0
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define aconf __elision_aconf
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Adaptive lock using transactions.
|
|
|
ce426f |
+ By default the lock region is run as a transaction, and when it
|
|
|
ce426f |
+ aborts or the lock is busy the lock adapts itself. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+int
|
|
|
ce426f |
+__lll_lock_elision (int *futex, short *adapt_count, EXTRAARG int private)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ if (*adapt_count <= 0)
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ unsigned status;
|
|
|
ce426f |
+ int try_xbegin;
|
|
|
ce426f |
+
|
|
|
ce426f |
+ for (try_xbegin = aconf.retry_try_xbegin;
|
|
|
ce426f |
+ try_xbegin > 0;
|
|
|
ce426f |
+ try_xbegin--)
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ if ((status = _xbegin()) == _XBEGIN_STARTED)
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ if (*futex == 0)
|
|
|
ce426f |
+ return 0;
|
|
|
ce426f |
+
|
|
|
ce426f |
+ /* Lock was busy. Fall back to normal locking.
|
|
|
ce426f |
+ Could also _xend here but xabort with 0xff code
|
|
|
ce426f |
+ is more visible in the profiler. */
|
|
|
ce426f |
+ _xabort (_ABORT_LOCK_BUSY);
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+
|
|
|
ce426f |
+ if (!(status & _XABORT_RETRY))
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ if ((status & _XABORT_EXPLICIT)
|
|
|
ce426f |
+ && _XABORT_CODE (status) == _ABORT_LOCK_BUSY)
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ /* Right now we skip here. Better would be to wait a bit
|
|
|
ce426f |
+ and retry. This likely needs some spinning. */
|
|
|
ce426f |
+ if (*adapt_count != aconf.skip_lock_busy)
|
|
|
ce426f |
+ *adapt_count = aconf.skip_lock_busy;
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+ /* Internal abort. There is no chance for retry.
|
|
|
ce426f |
+ Use the normal locking and next time use lock.
|
|
|
ce426f |
+ Be careful to avoid writing to the lock. */
|
|
|
ce426f |
+ else if (*adapt_count != aconf.skip_lock_internal_abort)
|
|
|
ce426f |
+ *adapt_count = aconf.skip_lock_internal_abort;
|
|
|
ce426f |
+ break;
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+ else
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ /* Use a normal lock until the threshold counter runs out.
|
|
|
ce426f |
+ Lost updates possible. */
|
|
|
ce426f |
+ (*adapt_count)--;
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+
|
|
|
ce426f |
+ /* Use a normal lock here. */
|
|
|
ce426f |
+ return LLL_LOCK ((*futex), private);
|
|
|
ce426f |
+}
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-timed.c
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-timed.c
|
|
|
ce426f |
@@ -0,0 +1,26 @@
|
|
|
ce426f |
+/* elision-timed.c: Lock elision timed lock.
|
|
|
ce426f |
+ Copyright (C) 2013 Free Software Foundation, Inc.
|
|
|
ce426f |
+ This file is part of the GNU C Library.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
ce426f |
+ modify it under the terms of the GNU Lesser General Public
|
|
|
ce426f |
+ License as published by the Free Software Foundation; either
|
|
|
ce426f |
+ version 2.1 of the License, or (at your option) any later version.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
ce426f |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
ce426f |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
ce426f |
+ Lesser General Public License for more details.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
ce426f |
+ License along with the GNU C Library; if not, see
|
|
|
ce426f |
+ <http://www.gnu.org/licenses/>. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+#include <time.h>
|
|
|
ce426f |
+#include <elision-conf.h>
|
|
|
ce426f |
+#include "lowlevellock.h"
|
|
|
ce426f |
+#define __lll_lock_elision __lll_timedlock_elision
|
|
|
ce426f |
+#define EXTRAARG const struct timespec *t,
|
|
|
ce426f |
+#undef LLL_LOCK
|
|
|
ce426f |
+#define LLL_LOCK(a, b) lll_timedlock(a, t, b)
|
|
|
ce426f |
+#include "elision-lock.c"
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-trylock.c
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-trylock.c
|
|
|
ce426f |
@@ -0,0 +1,72 @@
|
|
|
ce426f |
+/* elision-trylock.c: Lock eliding trylock for pthreads.
|
|
|
ce426f |
+ Copyright (C) 2013 Free Software Foundation, Inc.
|
|
|
ce426f |
+ This file is part of the GNU C Library.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
ce426f |
+ modify it under the terms of the GNU Lesser General Public
|
|
|
ce426f |
+ License as published by the Free Software Foundation; either
|
|
|
ce426f |
+ version 2.1 of the License, or (at your option) any later version.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
ce426f |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
ce426f |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
ce426f |
+ Lesser General Public License for more details.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
ce426f |
+ License along with the GNU C Library; if not, see
|
|
|
ce426f |
+ <http://www.gnu.org/licenses/>. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+#include <pthread.h>
|
|
|
ce426f |
+#include <pthreadP.h>
|
|
|
ce426f |
+#include <lowlevellock.h>
|
|
|
ce426f |
+#include "hle.h"
|
|
|
ce426f |
+#include <elision-conf.h>
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define aconf __elision_aconf
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Try to elide a futex trylock. FUTEX is the futex variable. TRY_LOCK is the
|
|
|
ce426f |
+ adaptation counter in the mutex. UPGRADED is != 0 when this is for an
|
|
|
ce426f |
+ automatically upgraded lock. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+int
|
|
|
ce426f |
+__lll_trylock_elision (int *futex, short *adapt_count)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ /* Implement POSIX semantics by forbiding nesting
|
|
|
ce426f |
+ trylock. Sorry. After the abort the code is re-executed
|
|
|
ce426f |
+ non transactional and if the lock was already locked
|
|
|
ce426f |
+ return an error. */
|
|
|
ce426f |
+ _xabort (_ABORT_NESTED_TRYLOCK);
|
|
|
ce426f |
+
|
|
|
ce426f |
+ /* Only try a transaction if it's worth it. */
|
|
|
ce426f |
+ if (*adapt_count <= 0)
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ unsigned status;
|
|
|
ce426f |
+
|
|
|
ce426f |
+ if ((status = _xbegin()) == _XBEGIN_STARTED)
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ if (*futex == 0)
|
|
|
ce426f |
+ return 0;
|
|
|
ce426f |
+
|
|
|
ce426f |
+ /* Lock was busy. Fall back to normal locking.
|
|
|
ce426f |
+ Could also _xend here but xabort with 0xff code
|
|
|
ce426f |
+ is more visible in the profiler. */
|
|
|
ce426f |
+ _xabort (_ABORT_LOCK_BUSY);
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+
|
|
|
ce426f |
+ if (!(status & _XABORT_RETRY))
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ /* Internal abort. No chance for retry. For future
|
|
|
ce426f |
+ locks don't try speculation for some time. */
|
|
|
ce426f |
+ if (*adapt_count != aconf.skip_trylock_internal_abort)
|
|
|
ce426f |
+ *adapt_count = aconf.skip_trylock_internal_abort;
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+ /* Could do some retries here. */
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+ else
|
|
|
ce426f |
+ {
|
|
|
ce426f |
+ /* Lost updates are possible, but harmless. */
|
|
|
ce426f |
+ (*adapt_count)--;
|
|
|
ce426f |
+ }
|
|
|
ce426f |
+
|
|
|
ce426f |
+ return lll_trylock (*futex);
|
|
|
ce426f |
+}
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-unlock.c
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-unlock.c
|
|
|
ce426f |
@@ -0,0 +1,33 @@
|
|
|
ce426f |
+/* elision-unlock.c: Commit an elided pthread lock.
|
|
|
ce426f |
+ Copyright (C) 2013 Free Software Foundation, Inc.
|
|
|
ce426f |
+ This file is part of the GNU C Library.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
ce426f |
+ modify it under the terms of the GNU Lesser General Public
|
|
|
ce426f |
+ License as published by the Free Software Foundation; either
|
|
|
ce426f |
+ version 2.1 of the License, or (at your option) any later version.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
ce426f |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
ce426f |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
ce426f |
+ Lesser General Public License for more details.
|
|
|
ce426f |
+
|
|
|
ce426f |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
ce426f |
+ License along with the GNU C Library; if not, see
|
|
|
ce426f |
+ <http://www.gnu.org/licenses/>. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+#include "pthreadP.h"
|
|
|
ce426f |
+#include "lowlevellock.h"
|
|
|
ce426f |
+#include "hle.h"
|
|
|
ce426f |
+
|
|
|
ce426f |
+int
|
|
|
ce426f |
+__lll_unlock_elision(int *lock, int private)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ /* When the lock was free we're in a transaction.
|
|
|
ce426f |
+ When you crash here you unlocked a free lock. */
|
|
|
ce426f |
+ if (*lock == 0)
|
|
|
ce426f |
+ _xend();
|
|
|
ce426f |
+ else
|
|
|
ce426f |
+ lll_unlock ((*lock), private);
|
|
|
ce426f |
+ return 0;
|
|
|
ce426f |
+}
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/hle.h
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- /dev/null
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/hle.h
|
|
|
ce426f |
@@ -0,0 +1,75 @@
|
|
|
ce426f |
+/* Shared RTM header. Emulate TSX intrinsics for compilers and assemblers
|
|
|
ce426f |
+ that do not support the intrinsics and instructions yet. */
|
|
|
ce426f |
+#ifndef _HLE_H
|
|
|
ce426f |
+#define _HLE_H 1
|
|
|
ce426f |
+
|
|
|
ce426f |
+#ifdef __ASSEMBLER__
|
|
|
ce426f |
+
|
|
|
ce426f |
+.macro XBEGIN target
|
|
|
ce426f |
+ .byte 0xc7,0xf8
|
|
|
ce426f |
+ .long \target-1f
|
|
|
ce426f |
+1:
|
|
|
ce426f |
+.endm
|
|
|
ce426f |
+
|
|
|
ce426f |
+.macro XEND
|
|
|
ce426f |
+ .byte 0x0f,0x01,0xd5
|
|
|
ce426f |
+.endm
|
|
|
ce426f |
+
|
|
|
ce426f |
+.macro XABORT code
|
|
|
ce426f |
+ .byte 0xc6,0xf8,\code
|
|
|
ce426f |
+.endm
|
|
|
ce426f |
+
|
|
|
ce426f |
+.macro XTEST
|
|
|
ce426f |
+ .byte 0x0f,0x01,0xd6
|
|
|
ce426f |
+.endm
|
|
|
ce426f |
+
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
+
|
|
|
ce426f |
+/* Official RTM intrinsics interface matching gcc/icc, but works
|
|
|
ce426f |
+ on older gcc compatible compilers and binutils.
|
|
|
ce426f |
+ We should somehow detect if the compiler supports it, because
|
|
|
ce426f |
+ it may be able to generate slightly better code. */
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define _XBEGIN_STARTED (~0u)
|
|
|
ce426f |
+#define _XABORT_EXPLICIT (1 << 0)
|
|
|
ce426f |
+#define _XABORT_RETRY (1 << 1)
|
|
|
ce426f |
+#define _XABORT_CONFLICT (1 << 2)
|
|
|
ce426f |
+#define _XABORT_CAPACITY (1 << 3)
|
|
|
ce426f |
+#define _XABORT_DEBUG (1 << 4)
|
|
|
ce426f |
+#define _XABORT_NESTED (1 << 5)
|
|
|
ce426f |
+#define _XABORT_CODE(x) (((x) >> 24) & 0xff)
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define _ABORT_LOCK_BUSY 0xff
|
|
|
ce426f |
+#define _ABORT_LOCK_IS_LOCKED 0xfe
|
|
|
ce426f |
+#define _ABORT_NESTED_TRYLOCK 0xfd
|
|
|
ce426f |
+
|
|
|
ce426f |
+#ifndef __ASSEMBLER__
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define __force_inline __attribute__((__always_inline__)) inline
|
|
|
ce426f |
+
|
|
|
ce426f |
+static __force_inline int _xbegin(void)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ int ret = _XBEGIN_STARTED;
|
|
|
ce426f |
+ asm volatile (".byte 0xc7,0xf8 ; .long 0" : "+a" (ret) :: "memory");
|
|
|
ce426f |
+ return ret;
|
|
|
ce426f |
+}
|
|
|
ce426f |
+
|
|
|
ce426f |
+static __force_inline void _xend(void)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ asm volatile (".byte 0x0f,0x01,0xd5" ::: "memory");
|
|
|
ce426f |
+}
|
|
|
ce426f |
+
|
|
|
ce426f |
+static __force_inline void _xabort(const unsigned int status)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ asm volatile (".byte 0xc6,0xf8,%P0" :: "i" (status) : "memory");
|
|
|
ce426f |
+}
|
|
|
ce426f |
+
|
|
|
ce426f |
+static __force_inline int _xtest(void)
|
|
|
ce426f |
+{
|
|
|
ce426f |
+ unsigned char out;
|
|
|
ce426f |
+ asm volatile (".byte 0x0f,0x01,0xd6 ; setnz %0" : "=r" (out) :: "memory");
|
|
|
ce426f |
+ return out;
|
|
|
ce426f |
+}
|
|
|
ce426f |
+
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
+#endif
|
|
|
ce426f |
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
|
|
|
ce426f |
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
|
|
|
ce426f |
@@ -427,6 +427,13 @@ LLL_STUB_UNWIND_INFO_END
|
|
|
ce426f |
: "memory", "cx", "cc", "r10", "r11"); \
|
|
|
ce426f |
result; })
|
|
|
ce426f |
|
|
|
ce426f |
+extern int __lll_timedlock_elision (int *futex, short *adapt_count,
|
|
|
ce426f |
+ const struct timespec *timeout,
|
|
|
ce426f |
+ int private) attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define lll_timedlock_elision(futex, adapt_count, timeout, private) \
|
|
|
ce426f |
+ __lll_timedlock_elision(&(futex), &(adapt_count), timeout, private)
|
|
|
ce426f |
+
|
|
|
ce426f |
#define lll_robust_timedlock(futex, timeout, id, private) \
|
|
|
ce426f |
({ int result, ignore1, ignore2, ignore3; \
|
|
|
ce426f |
__asm __volatile (LOCK_INSTR "cmpxchgl %1, %4\n\t" \
|
|
|
ce426f |
@@ -597,6 +604,22 @@ extern int __lll_timedwait_tid (int *tid
|
|
|
ce426f |
} \
|
|
|
ce426f |
__result; })
|
|
|
ce426f |
|
|
|
ce426f |
+extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
|
|
|
ce426f |
+ attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+extern int __lll_unlock_elision (int *lock, int private)
|
|
|
ce426f |
+ attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+extern int __lll_trylock_elision (int *lock, short *adapt_count)
|
|
|
ce426f |
+ attribute_hidden;
|
|
|
ce426f |
+
|
|
|
ce426f |
+#define lll_lock_elision(futex, adapt_count, private) \
|
|
|
ce426f |
+ __lll_lock_elision (&(futex), &(adapt_count), private)
|
|
|
ce426f |
+#define lll_unlock_elision(futex, private) \
|
|
|
ce426f |
+ __lll_unlock_elision (&(futex), private)
|
|
|
ce426f |
+#define lll_trylock_elision(futex, adapt_count) \
|
|
|
ce426f |
+ __lll_trylock_elision (&(futex), &(adapt_count))
|
|
|
ce426f |
+
|
|
|
ce426f |
#endif /* !__ASSEMBLER__ */
|
|
|
ce426f |
|
|
|
ce426f |
#endif /* lowlevellock.h */
|
|
|
ce426f |
Index: glibc-2.17-c758a686/sysdeps/i386/i686/multiarch/init-arch.c
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/sysdeps/i386/i686/multiarch/init-arch.c
|
|
|
ce426f |
+++ /dev/null
|
|
|
ce426f |
@@ -1 +0,0 @@
|
|
|
ce426f |
-#include <sysdeps/x86_64/multiarch/init-arch.c>
|
|
|
ce426f |
Index: glibc-2.17-c758a686/INSTALL
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/INSTALL
|
|
|
ce426f |
+++ glibc-2.17-c758a686/INSTALL
|
|
|
ce426f |
@@ -140,6 +140,9 @@ will be used, and CFLAGS sets optimizati
|
|
|
ce426f |
additional security risks to the system and you should enable it
|
|
|
ce426f |
only if you understand and accept those risks.
|
|
|
ce426f |
|
|
|
ce426f |
+`--enable-lock-elision=yes'
|
|
|
ce426f |
+ Enable lock elision for pthread mutexes and rwlocks by default.
|
|
|
ce426f |
+
|
|
|
ce426f |
`--build=BUILD-SYSTEM'
|
|
|
ce426f |
`--host=HOST-SYSTEM'
|
|
|
ce426f |
These options are for cross-compiling. If you specify both
|
|
|
ce426f |
Index: glibc-2.17-c758a686/config.h.in
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/config.h.in
|
|
|
ce426f |
+++ glibc-2.17-c758a686/config.h.in
|
|
|
ce426f |
@@ -180,6 +180,9 @@
|
|
|
ce426f |
/* Define if __stack_chk_guard canary should be randomized at program startup. */
|
|
|
ce426f |
#undef ENABLE_STACKGUARD_RANDOMIZE
|
|
|
ce426f |
|
|
|
ce426f |
+/* Define if lock elision should be enabled by default. */
|
|
|
ce426f |
+#undef ENABLE_LOCK_ELISION
|
|
|
ce426f |
+
|
|
|
ce426f |
/* Package description. */
|
|
|
ce426f |
#undef PKGVERSION
|
|
|
ce426f |
|
|
|
ce426f |
Index: glibc-2.17-c758a686/configure
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/configure
|
|
|
ce426f |
+++ glibc-2.17-c758a686/configure
|
|
|
ce426f |
@@ -750,6 +750,7 @@ enable_profile
|
|
|
ce426f |
enable_versioning
|
|
|
ce426f |
enable_oldest_abi
|
|
|
ce426f |
enable_stackguard_randomization
|
|
|
ce426f |
+enable_lock_elision
|
|
|
ce426f |
enable_add_ons
|
|
|
ce426f |
enable_hidden_plt
|
|
|
ce426f |
enable_bind_now
|
|
|
ce426f |
@@ -1405,6 +1406,9 @@ Optional Features:
|
|
|
ce426f |
--enable-stackguard-randomization
|
|
|
ce426f |
initialize __stack_chk_guard canary with a random
|
|
|
ce426f |
number at program start
|
|
|
ce426f |
+ --enable-lock-elision=yes/no
|
|
|
ce426f |
+ Enable lock elision for pthread mutexes and rwlocks
|
|
|
ce426f |
+ by default
|
|
|
ce426f |
--enable-add-ons[=DIRS...]
|
|
|
ce426f |
configure and build add-ons in DIR1,DIR2,... search
|
|
|
ce426f |
for add-ons if no parameter given
|
|
|
ce426f |
@@ -3716,6 +3720,18 @@ if test "$enable_stackguard_randomize" =
|
|
|
ce426f |
|
|
|
ce426f |
fi
|
|
|
ce426f |
|
|
|
ce426f |
+# Check whether --enable-lock-elision was given.
|
|
|
ce426f |
+if test "${enable_lock_elision+set}" = set; then :
|
|
|
ce426f |
+ enableval=$enable_lock_elision; enable_lock_elision=$enableval
|
|
|
ce426f |
+else
|
|
|
ce426f |
+ enable_lock_elision=no
|
|
|
ce426f |
+fi
|
|
|
ce426f |
+
|
|
|
ce426f |
+if test "$enable_lock_elision" = yes ; then
|
|
|
ce426f |
+ $as_echo "#define ENABLE_LOCK_ELISION 1" >>confdefs.h
|
|
|
ce426f |
+
|
|
|
ce426f |
+fi
|
|
|
ce426f |
+
|
|
|
ce426f |
# Check whether --enable-add-ons was given.
|
|
|
ce426f |
if test "${enable_add_ons+set}" = set; then :
|
|
|
ce426f |
enableval=$enable_add_ons;
|
|
|
ce426f |
Index: glibc-2.17-c758a686/configure.in
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/configure.in
|
|
|
ce426f |
+++ glibc-2.17-c758a686/configure.in
|
|
|
ce426f |
@@ -155,6 +155,15 @@ if test "$enable_stackguard_randomize" =
|
|
|
ce426f |
AC_DEFINE(ENABLE_STACKGUARD_RANDOMIZE)
|
|
|
ce426f |
fi
|
|
|
ce426f |
|
|
|
ce426f |
+AC_ARG_ENABLE([lock-elision],
|
|
|
ce426f |
+ AC_HELP_STRING([--enable-lock-elision[=yes/no]],
|
|
|
ce426f |
+ [Enable lock elision for pthread mutexes and rwlocks by default]),
|
|
|
ce426f |
+ [enable_lock_elision=$enableval],
|
|
|
ce426f |
+ [enable_lock_elision=no])
|
|
|
ce426f |
+if test "$enable_lock_elision" = yes ; then
|
|
|
ce426f |
+ AC_DEFINE(ENABLE_LOCK_ELISION)
|
|
|
ce426f |
+fi
|
|
|
ce426f |
+
|
|
|
ce426f |
dnl Generic infrastructure for drop-in additions to libc.
|
|
|
ce426f |
AC_ARG_ENABLE([add-ons],
|
|
|
ce426f |
AC_HELP_STRING([--enable-add-ons@<:@=DIRS...@:>@],
|
|
|
ce426f |
Index: glibc-2.17-c758a686/manual/install.texi
|
|
|
ce426f |
===================================================================
|
|
|
ce426f |
--- glibc-2.17-c758a686.orig/manual/install.texi
|
|
|
ce426f |
+++ glibc-2.17-c758a686/manual/install.texi
|
|
|
ce426f |
@@ -174,6 +174,9 @@ setuid and owned by @code{root}. The us
|
|
|
ce426f |
additional security risks to the system and you should enable it only if
|
|
|
ce426f |
you understand and accept those risks.
|
|
|
ce426f |
|
|
|
ce426f |
+@item --enable-lock-elision=yes
|
|
|
ce426f |
+Enable lock elision for pthread mutexes by default.
|
|
|
ce426f |
+
|
|
|
ce426f |
@item --build=@var{build-system}
|
|
|
ce426f |
@itemx --host=@var{host-system}
|
|
|
ce426f |
These options are for cross-compiling. If you specify both options and
|