Date: Sun, 02 Nov 2008 15:15:33 -0500 From: "Alexandre \"Sunny\" Kovalenko" <gaijin.k@gmail.com> To: Alexander Motin <mav@FreeBSD.org> Cc: FreeBSD acpi <freebsd-acpi@freebsd.org>, freebsd-mobile@FreeBSD.org Subject: Re: Is the C3 possible with SMP? Message-ID: <1225656933.1202.2.camel@RabbitsDen> In-Reply-To: <490DF584.5080506@FreeBSD.org> References: <490DF584.5080506@FreeBSD.org>
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On Sun, 2008-11-02 at 20:46 +0200, Alexander Motin wrote: > Hi. > > I have tried to enable C3 state on my Core2Duo laptop and found that it > is not working good. System HZ timer stops during CPU sleep. After some > investigation I have found that it is due to LAPIC timer used for HZ > stopped during C3 state (same as during AMD's C1E). > > So the question is: Is it possible (or planned) to make it work somehow? > For example, by using some external timer instead of LAPIC's one? > > ACPI reports about 20% less idle power consumption with C3 state > comparing to C2. It would be interesting to get additional half an hour > on battery. > You can get half way there by adding dev.cpu.1.cx_lowest=C3 to /etc/sysctl.conf I do realize that this is not The Solution, but it still saves battery. HTH, -- Alexandre "Sunny" Kovalenko (Олександр Коваленко)
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