diff mbox series

[v5,4/4] powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN

Message ID 20211109041119.1972927-5-npiggin@gmail.com (mailing list archive)
State Not Applicable
Headers show
Series shoot lazy tlbs | expand

Commit Message

Nicholas Piggin Nov. 9, 2021, 4:11 a.m. UTC 
On a 16-socket 192-core POWER8 system, a context switching benchmark
with as many software threads as CPUs (so each switch will go in and
out of idle), upstream can achieve a rate of about 1 million context
switches per second, due to contention on the mm refcount.

powerpc/64s meets the prerequisites for CONFIG_MMU_LAZY_TLB_SHOOTDOWN,
so enable the option. This increases the above benchmark to 118 million.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/Kconfig | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ba5b66189358..8a584414ef67 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -249,6 +249,7 @@  config PPC
 	select IRQ_FORCED_THREADING
 	select MMU_GATHER_PAGE_SIZE
 	select MMU_GATHER_RCU_TABLE_FREE
+	select MMU_LAZY_TLB_SHOOTDOWN		if PPC_BOOK3S_64
 	select MODULES_USE_ELF_RELA
 	select NEED_DMA_MAP_STATE		if PPC64 || NOT_COHERENT_CACHE
 	select NEED_SG_DMA_LENGTH