From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCHv2] x86: only check for two watchdog NMIs Date: Mon, 1 Feb 2016 17:33:26 +0000 Message-ID: <56AF96E6.7020302@citrix.com> References: <1454346592-27067-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aQIMU-0006Wb-UK for xen-devel@lists.xenproject.org; Mon, 01 Feb 2016 17:34:03 +0000 In-Reply-To: <1454346592-27067-1-git-send-email-david.vrabel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: David Vrabel , xen-devel@lists.xenproject.org Cc: Jan Beulich List-Id: xen-devel@lists.xenproject.org On 01/02/16 17:09, David Vrabel wrote: > Since the NMI handler can now recognize watchdog NMIs, make > check_nmi_watchdog() only check for at least two watchdog NMIs. This > prevents false negatives caused by other processors (which may be > being power managed by the BIOS) running at reduced clock frequencies. > > We check for more than one NMI since there are apparently systems > where the NMI works only once. > > This will also slightly speed up boot times since we only wait the > full 10 ticks if the NMI watchdog on one or more CPUs is not working. > > Signed-off-by: David Vrabel Reviewed-by: Andrew Cooper