Date: Wed, 08 Aug 2007 19:12:08 +0200 From: =?ISO-8859-1?Q?Stefan_E=DFer?= <se@freebsd.org> To: Kris Kennaway <kris@obsecurity.org> Cc: freebsd-acpi@freebsd.org, Scot Hetzel <swhetzel@gmail.com>, freebsd-stable@freebsd.org Subject: Re: powerd freeze with amd 5000 X2 but not with lower cpus Message-ID: <46B9F968.4030508@freebsd.org> In-Reply-To: <20070806174920.GA39742@rot26.obsecurity.org> References: <200707271109.51334.joao@matik.com.br> <200707290614.18469.joao@matik.com.br> <46AB160D.6040207@freebsd.org> <200708060928.36154.joao@matik.com.br> <790a9fff0708060854xb3f3e51n39a159ccf3f8b581@mail.gmail.com> <20070806174920.GA39742@rot26.obsecurity.org>
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Kris Kennaway schrieb: > On Mon, Aug 06, 2007 at 10:54:08AM -0500, Scot Hetzel wrote: >> On 8/6/07, JoaoBR <joao@matik.com.br> wrote: >>> Only to remember the problem only ocurres when loading powerd and seems the >>> freeze happens when cpu freq is upshifting not down. >>> >> Try setting: >> >> hint.acpi_throttle.0.disabled="1" >> >> in /boot/loader.conf, as acpi_throttle may be the cause of the freeze. > > FYI this worked for me. Well, I never understood why we don't make this the default,. Since throttling has a much higher impact on performance than on power consumption, it always is lowering the throughput per Watt value (or to use some other metric, it increases the "Joule for completion of a task" value). For systems that do not support EST or PowerNow! (or newer), it may still be better to have the CPU work unthrottled and then go into an extended halt instead of a simple halt (C0). In case of systems with low voltage modes, throttling may make the CPU draw significantly more power than in a higher clocked, reduced voltage mode. (I.e. 2GHz->1.6GHz at lower voltage draws less power than throttling 2GHz->1GHz at the nominal operating voltage ...) Throttling may be useful to prevent over-heating of certain CPUs under extreme load, but AFAIK these implement it without OS support (in on-chip hardware, since the days of the P4). So, IMHO, we should normally have acpi_throttle disabled in the default installation ... Regards, STefan
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