From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758577AbYASW3i (ORCPT ); Sat, 19 Jan 2008 17:29:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751270AbYASW3b (ORCPT ); Sat, 19 Jan 2008 17:29:31 -0500 Received: from mtaout02-winn.ispmail.ntl.com ([81.103.221.48]:31122 "EHLO mtaout02-winn.ispmail.ntl.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751222AbYASW3a (ORCPT ); Sat, 19 Jan 2008 17:29:30 -0500 From: Ian Campbell To: Andi Kleen Cc: mingo@elte.hu, hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org In-Reply-To: <200801191957.21832.ak@suse.de> References: <20080118627.198787000@suse.de> <20080118172720.86C4F14AAE@wotan.suse.de> <1200766548.32050.32.camel@cthulhu.hellion.org.uk> <200801191957.21832.ak@suse.de> Content-Type: text/plain Date: Sat, 19 Jan 2008 22:29:13 +0000 Message-Id: <1200781753.32050.42.camel@cthulhu.hellion.org.uk> Mime-Version: 1.0 X-Mailer: Evolution 2.12.2 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 192.168.1.223 X-SA-Exim-Mail-From: ijc@hellion.org.uk Subject: Re: [PATCH] [4/7] Convert TSC disabling to generic cpuid disable bitmap X-SA-Exim-Version: 4.2.1 (built Tue, 09 Jan 2007 17:23:22 +0000) X-SA-Exim-Scanned: Yes (on hopkins.hellion.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2008-01-19 at 19:57 +0100, Andi Kleen wrote: > On Saturday 19 January 2008 19:15:48 Ian Campbell wrote: > > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c > > index 6f5c74a..b3721fd 100644 > > --- a/arch/x86/xen/time.c > > +++ b/arch/x86/xen/time.c > > @@ -592,7 +592,7 @@ __init void xen_time_init(void) > > set_normalized_timespec(&wall_to_monotonic, > > -xtime.tv_sec, -xtime.tv_nsec); > > > > - setup_clear_cpu_cap(X86_FEATURE_TSC); > > + setup_force_cpu_cap(X86_FEATURE_TSC); > > Actually that would be only needed if someone else disabled TSC explicitely before. > > Simply deleting this should be sufficient. Does this patch work for you? Yes. > It would break if someone passes notsc to a Xen kernel, but then a lot of options make the kernel > break if you don't know what you're doing so that doesn't seem like a big issue. I'm happy either way. I think the Xen paravirt subsystem will use TSC where it has to due to the Xen architecture regardless of this setting. Ian. -- Ian Campbell Good day for overcoming obstacles. Try a steeplechase.