[PATCH] powerpc/64: Use tick accounting by default

Anton Blanchard anton at ozlabs.org
Sat May 20 00:41:12 AEST 2017


From: Anton Blanchard <anton at samba.org>

ppc64 is the only architecture that turns on VIRT_CPU_ACCOUNTING_NATIVE
by default. The overhead of this option is extremely high - a context
switch microbenchmark using sched_yield() is almost 20% slower.

To get finer grained user/hardirq/softirq statitics, the
IRQ_TIME_ACCOUNTING option can be used instead, which has much lower
overhead.

As such, disable this option by default. If a user really wants it,
they can still enable it manually.

Signed-off-by: Anton Blanchard <anton at samba.org>
---
 init/Kconfig | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 1d3475fc9496..a5c30acc1ede 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -342,8 +342,7 @@ config VIRT_CPU_ACCOUNTING
 
 choice
 	prompt "Cputime accounting"
-	default TICK_CPU_ACCOUNTING if !PPC64
-	default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
+	default TICK_CPU_ACCOUNTING
 
 # Kind of a stub config for the pure tick based cputime accounting
 config TICK_CPU_ACCOUNTING
-- 
2.11.0



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