From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753184Ab0EGWg6 (ORCPT ); Fri, 7 May 2010 18:36:58 -0400 Received: from hera.kernel.org ([140.211.167.34]:39201 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752732Ab0EGWg5 (ORCPT ); Fri, 7 May 2010 18:36:57 -0400 Date: Fri, 7 May 2010 22:36:41 GMT From: tip-bot for Jacob Pan Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de, jacob.jun.pan@linux.intel.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, jacob.jun.pan@linux.intel.com In-Reply-To: <1273269585-14346-1-git-send-email-jacob.jun.pan@linux.intel.com> References: <1273269585-14346-1-git-send-email-jacob.jun.pan@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mrst] x86: Avoid check hlt for newer cpus Message-ID: Git-Commit-ID: 2b107d93635616db0c3f893c8cc2e6d5cd8d77b2 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Fri, 07 May 2010 22:36:42 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 2b107d93635616db0c3f893c8cc2e6d5cd8d77b2 Gitweb: http://git.kernel.org/tip/2b107d93635616db0c3f893c8cc2e6d5cd8d77b2 Author: Jacob Pan AuthorDate: Fri, 7 May 2010 14:59:45 -0700 Committer: H. Peter Anvin CommitDate: Fri, 7 May 2010 15:31:17 -0700 x86: Avoid check hlt for newer cpus Check hlt instruction was targeted for some older CPUs. It is an expensive operation in that it takes 4 ticks to break out the check. We can avoid such check completely for newer x86 cpus (family >= 5). [ hpa: corrected family > 5 to family >= 5 ] Signed-off-by: Jacob Pan LKML-Reference: <1273269585-14346-1-git-send-email-jacob.jun.pan@linux.intel.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/bugs.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 01a2652..c39576c 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -86,7 +86,7 @@ static void __init check_fpu(void) static void __init check_hlt(void) { - if (paravirt_enabled()) + if (boot_cpu_data.x86 >= 5 || paravirt_enabled()) return; printk(KERN_INFO "Checking 'hlt' instruction... ");