Excerpts from Christophe Leroy's message of December 21, 2020 4:04 pm: > > > 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.
Yeah, I don't know how to do that (switch people's oldconfig from =N to =Y) otherwise (without renaming the option). I think it's enough though, experts should have said yes already :) > >> 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 That's nicer. Thanks, Nick
