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authorTony Luck <tony.luck@intel.com>2009-09-25 08:42:16 -0700
committerTony Luck <tony.luck@intel.com>2009-09-25 08:42:16 -0700
commit2c86963b093c1a0887dfc6b32c6e5ea3a80f2922 (patch)
treed1ed58dd0a644dd670e3724a575112fedd4b4250 /arch/ia64/oprofile
parent53cddfcc0e760d2b364878b6dadbd0c6d087cfae (diff)
downloadlinux-2c86963b093c1a0887dfc6b32c6e5ea3a80f2922.tar.gz
[IA64] implement ticket locks for Itanium
Back in January 2008 Nick Piggin implemented "ticket" spinlocks for X86 (See commit 314cdbefd1fd0a7acf3780e9628465b77ea6a836). IA64 implementation has a couple of differences because of the available atomic operations ... e.g. we have no fetchadd2 instruction that operates on a 16-bit quantity so we make ticket locks use a 32-bit word for each of the current ticket and now-serving values. Performance on uncontended locks is about 8% worse than the previous implementation, but this seems a good trade for determinism in the contended case. Performance impact on macro-level benchmarks is in the noise. Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/oprofile')
-rw-r--r--arch/ia64/oprofile/backtrace.c20
1 files changed, 1 insertions, 19 deletions
diff --git a/arch/ia64/oprofile/backtrace.c b/arch/ia64/oprofile/backtrace.c
index adb01566bd57..5cdd7e4a597c 100644
--- a/arch/ia64/oprofile/backtrace.c
+++ b/arch/ia64/oprofile/backtrace.c
@@ -32,24 +32,6 @@ typedef struct
u64 *prev_pfs_loc; /* state for WAR for old spinlock ool code */
} ia64_backtrace_t;
-#if (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
-/*
- * Returns non-zero if the PC is in the spinlock contention out-of-line code
- * with non-standard calling sequence (on older compilers).
- */
-static __inline__ int in_old_ool_spinlock_code(unsigned long pc)
-{
- extern const char ia64_spinlock_contention_pre3_4[] __attribute__ ((weak));
- extern const char ia64_spinlock_contention_pre3_4_end[] __attribute__ ((weak));
- unsigned long sc_start = (unsigned long)ia64_spinlock_contention_pre3_4;
- unsigned long sc_end = (unsigned long)ia64_spinlock_contention_pre3_4_end;
- return (sc_start && sc_end && pc >= sc_start && pc < sc_end);
-}
-#else
-/* Newer spinlock code does a proper br.call and works fine with the unwinder */
-#define in_old_ool_spinlock_code(pc) 0
-#endif
-
/* Returns non-zero if the PC is in the Interrupt Vector Table */
static __inline__ int in_ivt_code(unsigned long pc)
{
@@ -80,7 +62,7 @@ static __inline__ int next_frame(ia64_backtrace_t *bt)
*/
if (bt->prev_pfs_loc && bt->regs && bt->frame.pfs_loc == bt->prev_pfs_loc)
bt->frame.pfs_loc = &bt->regs->ar_pfs;
- bt->prev_pfs_loc = (in_old_ool_spinlock_code(bt->frame.ip) ? bt->frame.pfs_loc : NULL);
+ bt->prev_pfs_loc = NULL;
return unw_unwind(&bt->frame) == 0;
}