powerpc: More elision improvements

__lll_trylock_elision sets the adapt_count variable too
aggressively, and incorrectly on persistent aborts.  Taking
a cue from s390, adapt_count is only updated if the lock
is locked, or a persistent failure occurs.

In addition, the abort codes have been renumbered and
refactored for clarity.  As it stands, glibc only cares
if the abort is persistent or not.

All aborts are now persistent, excepting a busy lock.  This
includes changing _ABORT_NESTED_TRYLOCK into a persistent
abort.

	* sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
	(__lll_trylock_elision): Fix setting of adapt_count.
	* sysdeps/unix/sysv/linux/powerpc/htm.h
	(_ABORT_PERSISTENT): Define to clarify persistent aborts.
	(_ABORT_NESTED_TRYLOCK): Renumber, and make persistent.
	(_ABORT_SYSCALL): Renumber, and clarify definition.
	(_ABORT_LOCK_BUSY): Renumber, make non-persistent.

diff --git a/ChangeLog b/ChangeLog
index 12cfb98fac56a20f61ba2729499a9b9931dd5907..a5440e2a74df3fae5ee15ae2ca5f77c4d5769708 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2015-11-19  Paul E. Murphy  <murphyp@linux.vnet.ibm.com>
+
+       * sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
+       (__lll_trylock_elision): Fix setting of adapt_count.
+       * sysdeps/unix/sysv/linux/powerpc/htm.h
+       (_ABORT_PERSISTENT): Define to clarify persistent aborts.
+       (_ABORT_NESTED_TRYLOCK): Renumber, and make persistent.
+       (_ABORT_SYSCALL): Renumber, and clarify definition.
+       (_ABORT_LOCK_BUSY): Renumber, make non-persistent.
+
 2015-11-19  Paul E. Murphy  <murphyp@linux.vnet.ibm.com>
 
        * sysdeps/ieee754/ldbl-128ibm/mpn2ldl.c: Include gmp headers

diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-trylock.c b/sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
index 440939cda155b170e13447eb523ab9783cce9d7d..6f61eba48e221c527ba2a4c76276cef2c0cb1f97 100644 (file)
--- a/sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
+++ b/sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
@@ -44,8 +44,12 @@ __lll_trylock_elision (int *futex, short *adapt_count)
       if (*futex == 0)
        return 0;
 
-      /* Lock was busy.  Fall back to normal locking.  */
-      __builtin_tabort (_ABORT_LOCK_BUSY);
+      /* Lock was busy.  This is never a nested transaction.
+         End it, and set the adapt count.  */
+      __builtin_tend (0);
+
+      if (aconf.skip_lock_busy > 0)
+       *adapt_count = aconf.skip_lock_busy;
     }
   else
     {
@@ -57,9 +61,6 @@ __lll_trylock_elision (int *futex, short *adapt_count)
          if (aconf.skip_trylock_internal_abort > 0)
            *adapt_count = aconf.skip_trylock_internal_abort;
        }
-
-       if (aconf.skip_lock_busy > 0)
-         *adapt_count = aconf.skip_lock_busy;
     }
 
 use_lock:

diff --git a/sysdeps/unix/sysv/linux/powerpc/htm.h b/sysdeps/unix/sysv/linux/powerpc/htm.h
index 57d5cd62620340ccd932dd913b8d0621ef8c5863..5127b4bf0a38e0bbaef776265fc65207f6d5298c 100644 (file)
--- a/sysdeps/unix/sysv/linux/powerpc/htm.h
+++ b/sysdeps/unix/sysv/linux/powerpc/htm.h
@@ -129,10 +129,12 @@
 
 #endif /* __ASSEMBLER__ */
 
-/* Definitions used for TEXASR Failure code (bits 0:6), they need to be even
-   because tabort. always sets the first bit.  */
-#define _ABORT_LOCK_BUSY       0x3f   /* Lock already used.  */
-#define _ABORT_NESTED_TRYLOCK  0x3e   /* Write operation in trylock.  */
-#define _ABORT_SYSCALL         0x3d   /* Syscall issued.  */
+/* Definitions used for TEXASR Failure code (bits 0:7).  If the failure
+   should be persistent, the abort code must be odd.  0xd0 through 0xff
+   are reserved for the kernel and potential hypervisor.  */
+#define _ABORT_PERSISTENT      0x01   /* An unspecified persistent abort.  */
+#define _ABORT_LOCK_BUSY       0x34   /* Busy lock, not persistent.  */
+#define _ABORT_NESTED_TRYLOCK  (0x32 | _ABORT_PERSISTENT)
+#define _ABORT_SYSCALL         (0x30 | _ABORT_PERSISTENT)
 
 #endif