From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755231AbYANI2g (ORCPT ); Mon, 14 Jan 2008 03:28:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754832AbYANI2W (ORCPT ); Mon, 14 Jan 2008 03:28:22 -0500 Received: from viefep18-int.chello.at ([213.46.255.22]:20777 "EHLO viefep33-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754806AbYANI2U (ORCPT ); Mon, 14 Jan 2008 03:28:20 -0500 Subject: Re: [PATCH] Remove timer frequency choice if tickless is enabled From: Peter Zijlstra To: Ingo Molnar Cc: "Carlos R. Mafra" , linux-kernel@vger.kernel.org In-Reply-To: <20080114082543.GC18296@elte.hu> References: <20080112020026.GB5849@Pilar.physics.ucla.edu> <20080112032718.GA3946@Pilar.socal.rr.com> <20080114082543.GC18296@elte.hu> Content-Type: text/plain Date: Mon, 14 Jan 2008 09:28:15 +0100 Message-Id: <1200299295.7415.0.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.21.4 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2008-01-14 at 09:25 +0100, Ingo Molnar wrote: > (lkml Cc:-ed) > > * Carlos R. Mafra wrote: > > > choice > > prompt "Timer frequency" > > + depends on !NO_HZ > > default HZ_250 > > help > > Allows the configuration of the timer frequency. It is customary > > we are not there yet to be able to do this. With NO_HZ the tick is only > disabled when we go idle - but it still runs (and we rely on it, for > example in the scheduler code) while we are non-idle. Peter Zijlstra is > working on the 'high-res scheduler tick' feature to remove the scheduler > dependencies. Yes, and even then we're still not there, there are various other features that are tick driven, among them the RCU quiecent state machine.