Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752885Ab3JZNvj (ORCPT ); Sat, 26 Oct 2013 09:51:39 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37238 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752695Ab3JZNvb (ORCPT ); Sat, 26 Oct 2013 09:51:31 -0400 Date: Sat, 26 Oct 2013 06:50:56 -0700 From: tip-bot for Raghavendra K T Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, konrad.wilk@oracle.com, a.p.zijlstra@chello.nl, torvalds@linux-foundation.org, gleb@redhat.com, raghavendra.kt@linux.vnet.ibm.com, akpm@linux-foundation.org, pbonzini@redhat.com, tglx@linutronix.de, linux@eikelenboom.it Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, konrad.wilk@oracle.com, torvalds@linux-foundation.org, a.p.zijlstra@chello.nl, gleb@redhat.com, raghavendra.kt@linux.vnet.ibm.com, akpm@linux-foundation.org, pbonzini@redhat.com, linux@eikelenboom.it, tglx@linutronix.de In-Reply-To: <1382371508-3843-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> References: <1382371508-3843-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/locking] x86/locking/kconfig: Update paravirt spinlock Kconfig description Git-Commit-ID: 4c4e4f61368164f326fe59e2156c70d7faa72c17 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.1 (terminus.zytor.com [127.0.0.1]); Sat, 26 Oct 2013 06:51:04 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2405 Lines: 62 Commit-ID: 4c4e4f61368164f326fe59e2156c70d7faa72c17 Gitweb: http://git.kernel.org/tip/4c4e4f61368164f326fe59e2156c70d7faa72c17 Author: Raghavendra K T AuthorDate: Mon, 21 Oct 2013 21:35:08 +0530 Committer: Ingo Molnar 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 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(-) 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-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/