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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/Kconfig
parent53cddfcc0e760d2b364878b6dadbd0c6d087cfae (diff)
[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/Kconfig')
-rw-r--r--arch/ia64/Kconfig4
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 6851e52ed5a..1ee596cd942 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