From 4c4e4f61368164f326fe59e2156c70d7faa72c17 Mon Sep 17 00:00:00 2001 From: Raghavendra K T Date: Mon, 21 Oct 2013 21:35:08 +0530 Subject: x86/locking/kconfig: Update paravirt spinlock Kconfig description Since the paravirt spinlock optimizations went into the v3.12 kernel we have a very good performance benefit for paravirtualized KVM / Xen kernels. Also we no longer suffer from 5% side effect on native kernel that is mentioned in the Kconfig entry. So update the Kconfig entry accordingly. pvspinlock benefit on KVM link: https://lkml.org/lkml/2013/8/6/178 Attilio's tests on native kernel impact: http://blog.xen.org/index.php/2012/05/11/benchmarking-the-new-pv-ticketlock-implementation/ Signed-off-by: Raghavendra K T Cc: Cc: Cc: Cc: Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1382371508-3843-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com [ Updated the changelog. ] Signed-off-by: Ingo Molnar --- arch/x86/Kconfig | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/x86/Kconfig') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ee2fb9d..a92572d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -638,10 +638,10 @@ config PARAVIRT_SPINLOCKS spinlock implementation with something virtualization-friendly (for example, block the virtual CPU rather than spinning). - Unfortunately the downside is an up to 5% performance hit on - native kernels, with various workloads. + It has a minimal impact on native kernels and gives a nice performance + benefit on paravirtualized KVM / Xen kernels. - If you are unsure how to answer this question, answer N. + If you are unsure how to answer this question, answer Y. source "arch/x86/xen/Kconfig" -- cgit v1.1