Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941607AbXHJUb3 (ORCPT ); Fri, 10 Aug 2007 16:31:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933697AbXHJUa5 (ORCPT ); Fri, 10 Aug 2007 16:30:57 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:42527 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932508AbXHJUa4 (ORCPT ); Fri, 10 Aug 2007 16:30:56 -0400 Date: Fri, 10 Aug 2007 13:30:55 -0700 From: "Paul E. McKenney" To: Andrew Morton Cc: Adrian Bunk , Josh Triplett , linux-kernel@vger.kernel.org Subject: Re: 2.6.23-rc2-mm1: rcutorture xtime usage Message-ID: <20070810203055.GE8511@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20070809015106.cd0bfc53.akpm@linux-foundation.org> <20070810013146.GD18938@stusta.de> <20070810020040.GK8424@linux.vnet.ibm.com> <20070809190623.f60dcf70.akpm@linux-foundation.org> <20070810151208.GC8511@linux.vnet.ibm.com> <20070810101212.d59ce24a.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070810101212.d59ce24a.akpm@linux-foundation.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1182 Lines: 31 On Fri, Aug 10, 2007 at 10:12:12AM -0700, Andrew Morton wrote: > On Fri, 10 Aug 2007 08:12:08 -0700 "Paul E. McKenney" wrote: > > > > One used to use sched_clock() for this, then get frowned at. Now we > > > have cpu_clock()... > > > > Hmmm... And cpu_clock() is not in 2.6.22, so must appear in some later > > release. Which means that the rate of API change in this area is a > > bit high, so I should avoid it like the plague. > > eh, it's been there for weeks. It is dust-encrusted. > > > Therefore, I should > > look for some other convenient source of entropy. > > > > One convenient source would the per-CPU statistics that rcutorture > > maintains. Of course, a given CPU's RNG is nearly in lock-step with > > its own statistics, but not with the adjacent CPU's statistics... > > > > I will send a patch. > > Please use cpu_clock(). It ain't going away. D'accord... Thanx, Paul - 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/