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/Kconfig | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'arch/ia64/Kconfig') diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig index 6851e52..1ee596c 100644 --- a/arch/ia64/Kconfig +++ b/arch/ia64/Kconfig @@ -60,9 +60,7 @@ config IOMMU_HELPER bool config GENERIC_LOCKBREAK - bool - default y - depends on SMP && PREEMPT + def_bool n config RWSEM_XCHGADD_ALGORITHM bool -- cgit v1.1