search for: ppc_queued_spinlocks

...nfig b/arch/powerpc/Kconfig index 9fa23eb320ff..b17575109876 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -145,6 +145,8 @@ config PPC select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if PPC64 + select ARCH_USE_QUEUED_RWLOCKS if PPC_QUEUED_SPINLOCKS + select ARCH_USE_QUEUED_SPINLOCKS if PPC_QUEUED_SPINLOCKS select ARCH_WANT_IPC_PARSE_VERSION select ARCH_WEAK_RELEASE_ACQUIRE select BINFMT_ELF @@ -490,6 +492,17 @@ config HOTPLUG_CPU Say N if you are unsure. +config PPC_QUEUED_SPINLOCKS + bool "Queued spinlocks" + depends...

...nfig b/arch/powerpc/Kconfig index 24ac85c868db..17663ea57697 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -146,6 +146,8 @@ config PPC select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if PPC64 + select ARCH_USE_QUEUED_RWLOCKS if PPC_QUEUED_SPINLOCKS + select ARCH_USE_QUEUED_SPINLOCKS if PPC_QUEUED_SPINLOCKS select ARCH_WANT_IPC_PARSE_VERSION select ARCH_WEAK_RELEASE_ACQUIRE select BINFMT_ELF @@ -492,6 +494,17 @@ config HOTPLUG_CPU Say N if you are unsure. +config PPC_QUEUED_SPINLOCKS + bool "Queued spinlocks" + depends...

...e need for that part? > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 24ac85c868db..17663ea57697 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -492,6 +494,17 @@ config HOTPLUG_CPU > > Say N if you are unsure. > > +config PPC_QUEUED_SPINLOCKS > + bool "Queued spinlocks" > + depends on SMP > + default "y" if PPC_BOOK3S_64 Not sure about default y? At least until we've got a better idea of the perf impact on a range of small/big new/old systems. > + help > + Say Y here to use to use queued spinlo...

v2 is updated to account for feedback from Will, Peter, and Waiman (thank you), and trims off a couple of RFC and unrelated patches. Thanks, Nick Nicholas Piggin (6): powerpc/powernv: must include hvcall.h to get PAPR defines powerpc/pseries: move some PAPR paravirt functions to their own file powerpc: move spinlock implementation to simple_spinlock powerpc/64s: implement queued

Updated with everybody's feedback (thanks all), and more performance results. What I've found is I might have been measuring the worst load point for the paravirt case, and by looking at a range of loads it's clear that queued spinlocks are overall better even on PV, doubly so when you look at the generally much improved worst case latencies. I have defaulted it to N even though

...b/arch/powerpc/platforms/pseries/Kconfig @@ -25,9 +25,14 @@ config PPC_PSERIES select SWIOTLB default y +config PARAVIRT_SPINLOCKS + bool + default n + config PPC_SPLPAR depends on PPC_PSERIES bool "Support for shared-processor logical partitions" + select PARAVIRT_SPINLOCKS if PPC_QUEUED_SPINLOCKS help Enabling this option will make the kernel run more efficiently on logically-partitioned pSeries systems which use shared diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 2db8469e475f..747a203d9453 100644 --- a/arch/powerpc/platforms/p...

v3 is updated to use __pv_queued_spin_unlock, noticed by Waiman (thank you). Thanks, Nick Nicholas Piggin (6): powerpc/powernv: must include hvcall.h to get PAPR defines powerpc/pseries: move some PAPR paravirt functions to their own file powerpc: move spinlock implementation to simple_spinlock powerpc/64s: implement queued spinlocks and rwlocks powerpc/pseries: implement paravirt

v3 is updated to use __pv_queued_spin_unlock, noticed by Waiman (thank you). Thanks, Nick Nicholas Piggin (6): powerpc/powernv: must include hvcall.h to get PAPR defines powerpc/pseries: move some PAPR paravirt functions to their own file powerpc: move spinlock implementation to simple_spinlock powerpc/64s: implement queued spinlocks and rwlocks powerpc/pseries: implement paravirt

...b/arch/powerpc/platforms/pseries/Kconfig @@ -25,9 +25,14 @@ config PPC_PSERIES select SWIOTLB default y +config PARAVIRT_SPINLOCKS + bool + default n + config PPC_SPLPAR depends on PPC_PSERIES bool "Support for shared-processor logical partitions" + select PARAVIRT_SPINLOCKS if PPC_QUEUED_SPINLOCKS help Enabling this option will make the kernel run more efficiently on logically-partitioned pSeries systems which use shared diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 2db8469e475f..747a203d9453 100644 --- a/arch/powerpc/platforms/p...

...b/arch/powerpc/platforms/pseries/Kconfig @@ -25,9 +25,14 @@ config PPC_PSERIES select SWIOTLB default y +config PARAVIRT_SPINLOCKS + bool + default n + config PPC_SPLPAR depends on PPC_PSERIES bool "Support for shared-processor logical partitions" + select PARAVIRT_SPINLOCKS if PPC_QUEUED_SPINLOCKS help Enabling this option will make the kernel run more efficiently on logically-partitioned pSeries systems which use shared diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 2db8469e475f..747a203d9453 100644 --- a/arch/powerpc/platforms/p...

This series adds an option to use queued spinlocks for powerpc, and makes it the default for the Book3S-64 subarch. This effort starts with the generic code so it's very simple but still very performant. There are optimisations that can be made to slowpaths, but I think it's better to attack those incrementally if/when we find things, and try to add the improvements to generic code as