Subject: [PATCH 8/8] powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN

From: Nicholas Piggin <[email-masked]>
Date: Sun, 29 Nov 2020 02:01:41 +1000

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. After this patch it goes up to 118 million.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e9f13fe08492..d4793c0229d2 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -231,6 +231,7 @@ config PPC
 	select HAVE_PERF_USER_STACK_DUMP
 	select MMU_GATHER_RCU_TABLE_FREE
 	select MMU_GATHER_PAGE_SIZE
+	select MMU_LAZY_TLB_SHOOTDOWN		if PPC_BOOK3S_64
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE		if PPC_BOOK3S_64 && CPU_LITTLE_ENDIAN
 	select HAVE_SYSCALL_TRACEPOINTS
-- 
2.23.0