Commit-ID: 4c4e4f61368164f326fe59e2156c70d7faa72c17 Gitweb: http://git.kernel.org/tip/4c4e4f61368164f326fe59e2156c70d7faa72c17 Author: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx> AuthorDate: Mon, 21 Oct 2013 21:35:08 +0530 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Sat, 26 Oct 2013 12:23:22 +0200 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 <raghavendra.kt@xxxxxxxxxxxxxxxxxx> Cc: <konrad.wilk@xxxxxxxxxx> Cc: <linux@xxxxxxxxxxxxxx> Cc: <gleb@xxxxxxxxxx> Cc: <pbonzini@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Link: http://lkml.kernel.org/r/1382371508-3843-1-git-send-email-raghavendra.kt@xxxxxxxxxxxxxxxxxx [ Updated the changelog. ] Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/Kconfig | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) 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" -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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