Date: Wed, 10 Aug 2005 12:01:18 +0200 From: Tijl Coosemans <tijl@ulyssis.org> To: freebsd-acpi@freebsd.org Cc: ducrot@freebsd.org Subject: Re: 5-STABLE cpufreq hotter than est from ports Message-ID: <200508101201.19489.tijl@ulyssis.org> In-Reply-To: <20050808180345.CABF35D08@ptavv.es.net> References: <20050808180345.CABF35D08@ptavv.es.net>
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On Monday 08 August 2005 20:03, Kevin Oberman wrote: > > From: Tijl Coosemans <tijl@ulyssis.org> > > Date: Mon, 8 Aug 2005 16:18:00 +0200 > > > > 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. > > Odd. I don't see that at all. I am running at either 1.8 GHz or 1.2 > GHz and the performance ramps almost in lock-step with the setting > and power consumption does, as well. Without your patch, using the > values of dev.cpu.0.freq that run the CPU at the slower speed (1.2 > GHz), I get the following: > dev.cpu.0.freq Temp. Savings > 1200 73 > 1050 69 5.5% > 750 64 12.3% > 600 62 15.1% > 300 58 20.5% > 150 54 25.0% > The lowest 1.8 GHz value (1350) results in 85.I find these power > savings to be significant. > > For power consumption I run the CPU at 100% until the CPU temperature > stabilizes. I realize that this is only an approximation of power > consumption, but I think it's close enough. I've done this too now and I must admit throttling does seem to have an=20 effect on power consumption, though it seems to be less and less=20 effective with lower absolute settings. 1600/100% (1600) 69=B0C 1600/12.5% (200) 55=B0C 600/100% (600) 48=B0C 600/12.5% (75) 45=B0C =46or me, dropping to the lowest frequency (75MHz) is just way too=20 expensive.
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