From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Jones Subject: Re: Dynamic frequency governor Date: Mon, 20 Oct 2003 16:39:37 +0100 Sender: cpufreq-bounces@www.linux.org.uk Message-ID: <20031020153936.GM2729@redhat.com> References: Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: cpufreq-bounces@www.linux.org.uk Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Moore, Robert" Cc: "Walz, Michael" , cpufreq@www.linux.org.uk On Mon, Oct 20, 2003 at 08:31:08AM -0700, Moore, Robert wrote: > > I'm planning on integrating the previously released Linux IST (Intel > Speedstep) driver into the CpuFreq architecture. Cool, but what does it do that the existing cpufreq speedstep drivers don't ? > I think that what is gained by having this code in the kernel is that a > very accurate measure of percent CPU utilization can be obtained > directly from the kernel idle handler, and there is less overhead during > the periodic sampling of the current CPU utilization by a timer thread. I'm not disputing whether or not putting this in the kernel is a good or bad thing (for the record, I think it's a good idea), however the fact remains, whilst there are folks owning patents on this, it'll *never* be acceptable for merging without an exception grant from the patent holder. Dave > From: Dave Jones [mailto:davej@redhat.com] > Sent: Sunday, October 19, 2003 6:24 AM > To: Moore, Robert > Cc: cpufreq@www.linux.org.uk > Subject: Re: Dynamic frequency governor > > On Fri, Oct 17, 2003 at 02:14:38PM -0700, Moore, Robert wrote: > > > I've been chartered to implement a multi-state algorithm for Linux; > > this will be a new governor that adjusts the CPU frequency based upon > > percent CPU utilization as reported from the kernel idle handler. > > > > Has any work been done (or is being done) in this area? I don't want > to > > rewrite the wheel. > > There are several patents in this area (I think from Hitachi, I forget > exactly) It has come up before on the list, so should be in the > archives. Unless you can get a grant from the holder that it may be > used in GPL code, this has zero chance of being merged to mainline. > > Dave > > -- > Dave Jones http://www.codemonkey.org.uk ---end quoted text--- -- Dave Jones http://www.codemonkey.org.uk