Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755443Ab3CFVFc (ORCPT ); Wed, 6 Mar 2013 16:05:32 -0500 Received: from mga14.intel.com ([143.182.124.37]:16248 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750970Ab3CFVF3 (ORCPT ); Wed, 6 Mar 2013 16:05:29 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,797,1355126400"; d="scan'208";a="265554584" Message-ID: <5137AF96.6050003@linux.intel.com> Date: Wed, 06 Mar 2013 13:05:26 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130219 Thunderbird/17.0.3 MIME-Version: 1.0 To: Thomas Gleixner CC: Feng Tang , John Stultz , Ingo Molnar , Jason Gunthorpe , x86@kernel.org, Len Brown , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, gong.chen@linux.intel.com Subject: Re: [PATCH v3 4/5] clocksource: Enable clocksource_cyc2ns() to cover big cycles References: <1362554271-22382-1-git-send-email-feng.tang@intel.com> <1362554271-22382-5-git-send-email-feng.tang@intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 599 Lines: 18 On 03/06/2013 06:09 AM, Thomas Gleixner wrote: > > This breaks everything which does not have a 64/32bit divide > instruction. And you can't replace it with do_div() as that would > impose massive overhead on those architectures in the fast path. > Could we do the same kind of scaling-by-multiplication that we do in kernel/time.c for this? -hpa -- 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/