From 2c86963b093c1a0887dfc6b32c6e5ea3a80f2922 Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Fri, 25 Sep 2009 08:42:16 -0700 Subject: [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 --- arch/ia64/oprofile/backtrace.c | 20 +------------------- 1 file changed, 1 insertion(+), 19 deletions(-) (limited to 'arch/ia64/oprofile') diff --git a/arch/ia64/oprofile/backtrace.c b/arch/ia64/oprofile/backtrace.c index adb0156..5cdd7e4 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; } -- cgit v1.1