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| author | Tony Luck <tony.luck@intel.com> | 2009-09-25 17:42:16 +0200 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2009-09-25 17:42:16 +0200 |
| commit | 2c86963b093c1a0887dfc6b32c6e5ea3a80f2922 (patch) | |
| tree | d1ed58dd0a644dd670e3724a575112fedd4b4250 /arch/ia64/Kconfig | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 (diff) | |
| download | linux-2c86963b093c1a0887dfc6b32c6e5ea3a80f2922.tar.xz linux-2c86963b093c1a0887dfc6b32c6e5ea3a80f2922.zip | |
[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/Kconfig | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig index 6851e52ed5a2..1ee596cd942f 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 |