Date: Mon, 29 Aug 2005 22:03:34 -0700 From: Nate Lawson <nate@root.org> To: Tijl Coosemans <tijl@ulyssis.org> Cc: freebsd-acpi@freebsd.org, ducrot@freebsd.org Subject: Re: 5-STABLE cpufreq hotter than est from ports Message-ID: <4313E8A6.5040800@root.org> In-Reply-To: <200508081618.01362.tijl@ulyssis.org> References: <20050807201552.8D6975D07@ptavv.es.net> <200508081618.01362.tijl@ulyssis.org>
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Tijl Coosemans wrote: > Kevin, > > Thanks for your reply. I was beginning to think I sent my mail to the > wrong list. I've subscribed to freebsd-acpi@ now. For reference, the > issues (+patch) discussed are available at: > > http://lists.freebsd.org/pipermail/freebsd-stable/2005-August/017535.html > http://lists.freebsd.org/pipermail/freebsd-stable/2005-August/017536.html > > >>I have a P4m with ICHSS and P4TCC and I do hit both the problem of the >>wrong mode being selected when there is a tie for performance level >>and the case of lower performance resulting in higher power >>consumption. You can see the results of my testing in messages to >>freebsd-acpi@ archives. I have been wanting to write some patches to >>fix the problems, but have simply not had time, so these patches look >>great! > > > In my experience throttling doesn't really gain that much. There's > almost no difference between running at 600MHz/100% and 600MHz/12.5%, > except that it is 8 times slower, so I've set debug.cpufreq.lowest to > 400 to limit the performance drop. It should produce a linear savings in power but other factors may affect it. Think about a server that gets a 1 minute burst every hour. You definitely want to use all the power saving you can, including throttling, to get the most out of the other 59 minutes. > I've also slightly modified powerd to not jump to the maximum frequency, > but to step up one level at a time to save energy. I've been thinking, > since throttling doesn't gain much, it might be better for powerd to > use only absolute settings when stepping up, but that would require an > extra sysctl entry (dev.cpu.0.freq_abs or something). That has been committed also (via phk). > I've found references in the following files. There may be more of > course. > > sys/conf/files.i386 (line 258) > sys/conf/options.i386 (line 56) > sys/i386/conf/NOTES (line 133 + line 215). > sys/i386/i386/p4tcc.c (can be removed?) I just took care of this too since I had a moment. -- Nate
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