From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751221AbWFSBag (ORCPT ); Sun, 18 Jun 2006 21:30:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751252AbWFSBag (ORCPT ); Sun, 18 Jun 2006 21:30:36 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:13969 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S1751221AbWFSBag (ORCPT ); Sun, 18 Jun 2006 21:30:36 -0400 Subject: Re: [ckpatch][15/29] hz-no_default_250.patch From: Lee Revell To: Albert Cahalan Cc: linux-kernel@vger.kernel.org, kernel@kolivas.org, john stultz In-Reply-To: <787b0d920606181752j4b7c7309t9c0ab9bf8da1537a@mail.gmail.com> References: <787b0d920606181752j4b7c7309t9c0ab9bf8da1537a@mail.gmail.com> Content-Type: text/plain Date: Sun, 18 Jun 2006 21:30:31 -0400 Message-Id: <1150680632.4428.129.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2006-06-18 at 20:52 -0400, Albert Cahalan wrote: > > Make 250 HZ a value that is not selected by default and give some > > better recommendations in help. > > No, 250 is a good default. > > We can't reliably do 1000. There are many systems, including both > laptops and servers, which have a BIOS that uses SMM/SMI to grab > the CPU for longer than a millisecond. We'd lose clock ticks if > we had HZ at 1000. > Doesn't this become a non-issue with John Stultz's gettimeofday rework? > NTSC video is 59.94 fields per second. Though a sample rate of > double that would satisfy the Nyquest theory, in practice you > need to go to 4x to 5x the rate you want. This comes out to be > around 240 to 300 as a minimum. Realtime audio wants higher framerates than video. Of course many of these systems with the SMM bug are fatally broken for these applications. Lee