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authorRoland McGrath <roland@hack.frob.com>2014-06-26 09:31:11 -0700
committerRoland McGrath <roland@hack.frob.com>2014-06-26 09:31:11 -0700
commit52ae23b4bfa09fa1f42e3f659aaa057d1176d06b (patch)
tree7c61e56d7fbbb3c9f82994b5d3d778cc19ee48c2 /sysdeps/unix/sysv/linux/s390/elision-conf.c
parent39507e4a6c52d67780d194dae8cfb636e2dbb87e (diff)
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Move remaining S390 code out of nptl/.
Diffstat (limited to 'sysdeps/unix/sysv/linux/s390/elision-conf.c')
-rw-r--r--sysdeps/unix/sysv/linux/s390/elision-conf.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/s390/elision-conf.c b/sysdeps/unix/sysv/linux/s390/elision-conf.c
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@@ -0,0 +1,82 @@
+/* Lock elision tunable parameters.
+ Copyright (C) 2014 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <pthreadP.h>
+#include <elision-conf.h>
+#include <unistd.h>
+#include <dl-procinfo.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 to not attempt to use elision if a lock used up all retries
+ without success. Expressed in number of lock acquisition attempts. */
+ .skip_lock_out_of_tbegin_retries = 3,
+ /* How often we try 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. */
+ .try_tbegin = 3,
+ /* Same as SKIP_LOCK_INTERNAL_ABORT but for trylock. */
+ .skip_trylock_internal_abort = 3,
+ };
+
+/* Force elision for all new locks. This is used to decide whether existing
+ DEFAULT locks should be automatically upgraded to elision in
+ pthread_mutex_lock(). Disabled for suid programs. Only used when elision
+ is available. */
+
+int __pthread_force_elision attribute_hidden = 0;
+
+/* Initialize elison. */
+
+static void
+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;
+
+ __pthread_force_elision = __libc_enable_secure ? 0 : elision_available;
+}
+
+#ifdef SHARED
+# define INIT_SECTION ".init_array"
+# define MAYBE_CONST
+#else
+# define INIT_SECTION ".preinit_array"
+# define MAYBE_CONST const
+#endif
+
+void (*MAYBE_CONST __pthread_init_array []) (int, char **, char **)
+ __attribute__ ((section (INIT_SECTION), aligned (sizeof (void *)))) =
+{
+ &elision_init
+};