Date: Wed, 02 Mar 2005 17:37:05 -0800 From: Nate Lawson <nate@root.org> To: Kevin Oberman <oberman@es.net> Cc: current@FreeBSD.ORG Subject: Re: patch: p4tcc and speedstep cpufreq drivers Message-ID: <42266A41.2010907@root.org> In-Reply-To: <20050302235623.BA3925D07@ptavv.es.net> References: <20050302235623.BA3925D07@ptavv.es.net>
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Kevin Oberman wrote: >>Date: Wed, 02 Mar 2005 15:28:52 -0800 >>From: Nate Lawson <nate@root.org> >>If you look elsewhere, the design is stated more clearly and shows the >>reading that enabling On-Demand disables Automatic mode is incorrect. >> >>Intel Software Developer's Manual, Volume 3, 13.15.3: >>"If on-demand clock modulation and TM1 are both enabled and the thermal >>status of the processor is hot ..., clock modulation at the duty cycle >>specified by TM1 takes precedence, regardless of the setting of the >>on-demand clock modulation duty cycle." >> >>Empirical testing shows TM1 kicks in around 75C and THERMTRIP is >>somewhere near 100C. The separate THERMTRIP feature disables the >>processor completely if TM1 or 2 fail to stop the temperature from rising. >> >>http://www.digit-life.com/articles2/p4-throttling/ > > > OK. This makes me feel a bit better, but I still think I'll leave TCC > out of the equation as it makes the various frequency steps vary uneven > to the point that lowering dev.cpu.0.freq would increase performance > (and the reverse, as well) and it causes my system to hang when > throttled back too far. It never hangs with TCC disabled although my > lowest "frequency" is now just 150 MHz. > > By the way, I am still delighted in the cpufreq addition to the system. > It gives me excellent control of CPU speed to stretch my battery life. > All I really need is a desktop tool (maybe a gnome applet) to let me > adjust freq easily. I may just try to write that myself if I get some > time before someone else gets to it. I'll try to see if I can find a way to notice bad states and disable them automatically. Perhaps your CPU has some errata. Regarding the gnome applet, too late, marcus@ has done that. :) -- Nate
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