From: Anton Blanchard <anton@ozlabs.org>
To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
npiggin@gmail.com, mikey@neuling.org, cyrilbur@gmail.com
Cc: linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc/64: Use tick accounting by default
Date: Sat, 20 May 2017 00:41:12 +1000 [thread overview]
Message-ID: <20170519144112.15649-1-anton@ozlabs.org> (raw)
From: Anton Blanchard <anton@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@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
next reply other threads:[~2017-05-19 14:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-19 14:41 Anton Blanchard [this message]
2017-05-22 4:15 ` [PATCH] powerpc/64: Use tick accounting by default Michael Ellerman
2017-05-22 4:46 ` Nicholas Piggin
2017-05-22 5:13 ` Anton Blanchard
2022-05-25 8:36 ` Christophe Leroy
2017-05-22 7:26 ` Christophe LEROY
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