Date: Sat, 28 Jun 2008 17:38:40 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-acpi@freebsd.org Cc: David Wolfskill <david@catwhisker.org> Subject: Re: How/why would dev.cpu.0.freq_levels change??!? Message-ID: <200806281738.40672.jhb@freebsd.org> In-Reply-To: <20080627235319.GP70792@bunrab.catwhisker.org> References: <20080627235319.GP70792@bunrab.catwhisker.org>
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On Friday 27 June 2008 07:53:19 pm David Wolfskill wrote: > My laptop is a Dell Inspiron 8200; I (ab)use it moderately heavily: > this includes tracking RELENG_6, RELENG_7, & HEAD on it, daily. > > Lately there have been some times when "make buildworld" for RELENG_6 > has taken a lot longer than it used to ... and I noticed that the > fans were on, even though it was running fairly cool (around 50C; > during a "make buildworld, around 85C is more common) -- and that > the machine was typically "topping out" at half speed (1200 MHz). > > During these times, querying dev.cpu.0.freq_levels would yield a list > that did, ini fact, max out at 1200 MHz, when I know that it has gone up > to 2400 MHz in the past. > > When it does this, the only circumvention I've been able to find is a > power-cycle. Since I like to minimize disruption, this is annoying. > > This afternoon, it showed evidence of doing this stunt again, so I > carefully logged out, powered the machine off, waited about 5 minutes, > then powered it back on. > > But this time, I decided to fire up a little loop to display a timestamp > and the ooutput from "sysctl -n hw.acpi.thermal.tz0.temperature > dev.cpu.0.freq dev.cpu.0.freq_levels" every 5 seconds. > > Here's the interval in question: > > 1214609737,60.5C,300,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0 > 1214609742,59.5C,450,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0 > 1214609748,59.5C,450,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0 > 1214609752,57.5C,150,2400/0 2100/0 1800/0 1500/0 1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0 > 1214609757,57.5C,600,1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0 > 1214609762,56.5C,150,1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0 > 1214609767,56.5C,150,1200/0 1050/0 900/0 750/0 600/0 450/0 300/0 150/0 Looks like it lowered the temperature. Your BIOS might have decided to change the levels to force the CPU to throttle down to cool the system. -- John Baldwin
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