From: Nicholas Piggin <npiggin@gmail•com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail•com>
Subject: [PATCH] powerpc: always enable queued spinlocks for 64s, disable for others
Date: Mon, 21 Dec 2020 13:22:26 +1000 [thread overview]
Message-ID: <20201221032226.888758-1-npiggin@gmail.com> (raw)
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 <npiggin@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
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
+
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
--
2.23.0
next reply other threads:[~2020-12-21 3:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-21 3:22 Nicholas Piggin [this message]
2020-12-21 6:04 ` [PATCH] powerpc: always enable queued spinlocks for 64s, disable for others Christophe Leroy
2020-12-22 3:28 ` Nicholas Piggin
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