Date: Thu, 07 Feb 2008 20:56:05 -0800 From: "Kevin Oberman" <oberman@es.net> To: "Alexandre \"Sunny\" Kovalenko" <alex.kovalenko@verizon.net> Cc: acpi@freebsd.org, Hajimu UMEMOTO <ume@freebsd.org> Subject: Re: [RFC] Patch to enable temperature ceiling in powerd Message-ID: <20080208045605.15C874500E@ptavv.es.net> In-Reply-To: Your message of "Thu, 07 Feb 2008 20:47:56 EST." <1202435276.1157.90.camel@RabbitsDen>
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--==_Exmh_1202446565_99651P Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > Date: Thu, 07 Feb 2008 20:47:56 -0500 > From: "Alexandre \"Sunny\" Kovalenko" <alex.kovalenko@verizon.net> > Sender: owner-freebsd-acpi@freebsd.org > > > On Fri, 2008-02-08 at 00:50 +0900, Hajimu UMEMOTO wrote: > > Hi, > > > > >>>>> On Wed, 30 Jan 2008 17:56:19 -0500 > > >>>>> "Alexandre \"Sunny\" Kovalenko" <alex.kovalenko@verizon.net> said: > > > > alex.kovalenko> Some time ago I have put together patch for powerd, which allows user to > > alex.kovalenko> specify the temperature threshold at which powerd will lower CPU > > alex.kovalenko> frequency no matter what the load was at the time. I recently had to > > alex.kovalenko> adapt it to the 7.0-PRERELEASE for someone with the overheating laptop, > > alex.kovalenko> which got me to think that it might be useful for someone else yet. > > > > alex.kovalenko> Basic idea is fairly simple -- check temperature in TZ0 and, if it has > > alex.kovalenko> reached certain value, either override frequency with the lowest > > alex.kovalenko> available (in the case of 'max' setting) or change idle time to 100% and > > alex.kovalenko> let adaptive algorithm decrease frequency gradually. > > > > alex.kovalenko> I imagine it also could be poor man's substitute for the low noise > > alex.kovalenko> acoustic policy ;) > > > > alex.kovalenko> If there is an interest, I will go ahead and submit a PR, otherwise it > > alex.kovalenko> will live in the mail archives for someone to find. Any comments, > > alex.kovalenko> suggestions or criticisms are welcome. > > > > alex.kovalenko> Temperature threshold (in Celsius) could be set by means of '-T' command > > alex.kovalenko> line option (as in '-T 60'). > > > > Our kernel has passive cooling feature, already. Is it not enough for > > you? > I must have missed it somehow, if you could, please, point me in the > right direction I will really appreciate it. When the temperature reaches hw.acpi.thermal.tz0._PSV, the system will slow down until the CPU drops to a level below the _PSV value. The operation, if enabled, is under the control of BIOS (and/or the EC) and typically runs with substantial hysteresis, but is usually adequate for keeping the CPU temperature to a safe point. My Pentium-M 2GHz has a value of 94.5C for _PSV. This may seem very high, but the maximum "safe" operating temperature for the CPU is 100C, so it is designed for pretty high temperatures. Quiescent temperature runs about 51C and, during a CPU intensive operation such as a big build (e.g. make -j2 buildworld) will rise to near 80C. Before I blew two years of dust out of the heat sinks, I was seeing about 60C quiescent and about 95 during CPU intensive operations. Passive cooling was kicking in then and the temperature never went higher (although the build took longer). -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751 --==_Exmh_1202446565_99651P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (FreeBSD) Comment: Exmh version 2.5 06/03/2002 iD8DBQFHq+Dlkn3rs5h7N1ERAhK/AJwP23VOm9R57YAA6H1hK0uY1Q5OMQCfS8JI 98FLxBY8wRt2/7wFun7QeOk= =D3QH -----END PGP SIGNATURE----- --==_Exmh_1202446565_99651P--
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