Commit c9f34013 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: Always enable queued spinlocks for 64s, disable for others 



Queued spinlocks have shown to have good performance and fairness
properties even on smaller (2 socket) POWER systems. This selects them
automatically for 64s. For other platforms they are de-selected, the
standard spinlock is far simpler and smaller code, and single chips
with a handful of cores is unlikely to show any improvement.

CONFIG_EXPERT still allows this to be changed, e.g., to help debug
performance or correctness issues.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210118123451.1452206-1-npiggin@gmail.com
parent 9dd31b11

arch/powerpc/Kconfig

+2 −6
Original line number Diff line number Diff line
@@ -505,18 +505,14 @@ config HOTPLUG_CPU 
	  Say N if you are unsure.



config PPC_QUEUED_SPINLOCKS

	bool "Queued spinlocks"

	bool "Queued spinlocks" if EXPERT

	depends on SMP

	default PPC_BOOK3S_64

	help

	  Say Y here to use queued spinlocks which give better scalability and

	  fairness on large SMP and NUMA systems without harming single threaded

	  performance.



	  This option is currently experimental, the code is more complex and

	  less tested so it defaults to "N" for the moment.



	  If unsure, say "N".



config ARCH_CPU_PROBE_RELEASE

	def_bool y

	depends on HOTPLUG_CPU