From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261212AbULMW0p (ORCPT ); Mon, 13 Dec 2004 17:26:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261206AbULMWY0 (ORCPT ); Mon, 13 Dec 2004 17:24:26 -0500 Received: from mail-relay-2.tiscali.it ([213.205.33.42]:25008 "EHLO mail-relay-2.tiscali.it") by vger.kernel.org with ESMTP id S261241AbULMWVg (ORCPT ); Mon, 13 Dec 2004 17:21:36 -0500 Date: Mon, 13 Dec 2004 23:21:38 +0100 From: Andrea Arcangeli To: john stultz Cc: lkml Subject: Re: dynamic-hz Message-ID: <20041213222138.GP16322@dualathlon.random> References: <20041211142317.GF16322@dualathlon.random> <1102971389.1281.427.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1102971389.1281.427.camel@cog.beaverton.ibm.com> X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 13, 2004 at 12:56:29PM -0800, john stultz wrote: > Interesting patch, I know some folks have been asking about HZ=10k > recently, so this could help. Yes, they only need to pass HZ=10000 to the boot command line to make it work with 2.4. > The only bit that worries me a bit is the change from HZ->USER_HZ for > internal calculations. In my mind, USER_HZ should only be used for > converting internal system ticks to userspace-visible ticks. Changing > drivers to think about things in user-ticks confuses things a bit since > suddenly some kernel code is thinking in user-ticks and others in > system-ticks. It just muddles things a bit. I tried to make the smallest possible change to make the thing work, even if that sometime meant to think in user hz. The user_to_kernel_hz helper function converts back into kernel hz.