Le 21/12/2020 à 04:22, Nicholas Piggin a écrit :
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: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/Kconfig | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ae7391627054..1f9f9e64d638 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -255,6 +255,7 @@ config PPC
select PCI_MSI_ARCH_FALLBACKS if PCI_MSI
select PCI_SYSCALL if PCI
select PPC_DAWR if PPC64
+ select PPC_QUEUED_SPINLOCKS if !EXPERT && PPC_BOOK3S_64 &&
SMP
The condition is a bit complicated, and it doesn't set it to Y by default when
EXPERT is selected.
select RTC_LIB
select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE
@@ -506,16 +507,13 @@ config HOTPLUG_CPU
config PPC_QUEUED_SPINLOCKS
bool "Queued spinlocks"
depends on SMP
+ depends on EXPERT || PPC_BOOK3S_64
+
I would do:
config PPC_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
Christophe
