From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from baldric (baldric.uwo.ca [129.100.10.225]) by dsl2.external.hp.com (Postfix) with ESMTP id 9A0174866 for ; Fri, 19 Sep 2003 10:02:46 -0600 (MDT) Date: Fri, 19 Sep 2003 12:00:35 -0400 From: Carlos O'Donell To: Joel Soete Cc: Matthew Wilcox , parisc-linux@parisc-linux.org Subject: Re: [parisc-linux] sched_clock implementation Message-ID: <20030919160035.GG18225@systemhalted> References: <20030918203510.GD21596@parcelfarce.linux.theplanet.co.uk> <3F6B2199.8050402@tiscali.be> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <3F6B2199.8050402@tiscali.be> Sender: parisc-linux-admin@lists.parisc-linux.org Errors-To: parisc-linux-admin@lists.parisc-linux.org List-Help: List-Post: List-Subscribe: , List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: On Fri, Sep 19, 2003 at 03:32:41PM +0000, Joel Soete wrote: > Matthew Wilcox wrote: > > >Anyone want to do better than the lame implementation? ;-) > > > >----- Forwarded message from Andrew Morton ----- > > > >I'll be merging Ingo & Con's CPOU scheduler changes into Linus's tree soon. > > > >It does require that the architecture provides a new timing function: > > > >A lame implementation is: > > > >/* > >* Returns nanoseconds > >*/ > > > > > Hi Willy, > > (Certainly yet another stupid question but) to reach such accuracy we > would need to have access to some 'time device' with an accuracy better > then the nanosec (iirc 10^-9) (because it doesn't seems to me possible > to get enough accuracy with cpu clock < 10^9 ie 1Ghz: the most case for > parisc systems). Does it exist such device and where to start to read > some doc? We could use cr16 to get better accuracy. See list discussions about fast gettimeofday. c.