Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262205AbUCZTDd (ORCPT ); Fri, 26 Mar 2004 14:03:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264130AbUCZTDc (ORCPT ); Fri, 26 Mar 2004 14:03:32 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:41946 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262205AbUCZTDP (ORCPT ); Fri, 26 Mar 2004 14:03:15 -0500 Message-ID: <40647E65.7020903@pobox.com> Date: Fri, 26 Mar 2004 14:03:01 -0500 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030703 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Sridhar Samudrala CC: Edgar Toernig , davem@redhat.com, linux-kernel@vger.kernel.org, netdev@oss.sgi.com Subject: Re: [PATCH] Consolidate multiple implementations of jiffies-msecs conversions. References: <20040326014403.39388cb8.froese@gmx.de> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1366 Lines: 39 Sridhar Samudrala wrote: > On Fri, 26 Mar 2004, Edgar Toernig wrote: > > >>Sridhar Samudrala wrote: >> >>>The following patch to 2.6.5-rc2 consolidates 6 different implementations >>>of msecs to jiffies and 3 different implementation of jiffies to msecs. >>>All of them now use the generic msecs_to_jiffies() and jiffies_to_msecs() >>>that are added to include/linux/time.h >>>[...] >>>-#define MSECS(ms) (((ms)*HZ/1000)+1) >>>-return (((ms)*HZ+999)/1000); >>>+return (msecs / 1000) * HZ + (msecs % 1000) * HZ / 1000; >> >>Did you check that all users of the new version will work correctly >>with your rounding? Explicit round-up of delays is often required, >>especially when talking to hardware... > > > I don't see any issues with the 2.6 default HZ value of 1000 as they become > no-ops and there is no need for any rounding. > I guess you are referring to cases when HZ < 1000(ex: 100) and msecs is > less than 10. In those cases, the new version returns 0, whereas some of the > older versions return 1. We'll definitely want to return 1 rather than zero, for the uses in my drivers, at least... Jeff - 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/