Date: Fri, 21 Nov 2008 11:57:14 -0800 From: "Kevin Oberman" <oberman@es.net> To: martinko <gamato@users.sf.net> Cc: freebsd-acpi@freebsd.org, freebsd-mobile@freebsd.org Subject: Re: Is the C3 possible with SMP? Message-ID: <20081121195714.CEE4B45010@ptavv.es.net> In-Reply-To: Your message of "Thu, 20 Nov 2008 22:32:57 %2B0100." <gg4l29$po2$1@ger.gmane.org>
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--==_Exmh_1227297434_96508P Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > From: martinko <gamato@users.sf.net> > Date: Thu, 20 Nov 2008 22:32:57 +0100 > Sender: owner-freebsd-mobile@freebsd.org > > Alexandre "Sunny" Kovalenko wrote: > > On Mon, 2008-11-03 at 00:06 +0200, Alexander Motin wrote: > >> Alexandre "Sunny" Kovalenko wrote: > >>>> 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 > >> Thanks. > >> > >> 1. Looks like it does not kill the timer. > >> 2. I haven't got any benefit from it in idle state. According to > >> `acpiconf -i 0` I have about 13 Amps (IMHO more looks like Watts) with > >> both C2 and this half-to-C3, but only 11 Amps in full C3 (but without > >> timer). > >> 3. I have got about 10% benefit (33 Amps against 36) when cpu0 is 100% > >> busy while cpu1 is idle. > >> > > You would not happen to have USB loaded or built into kernel? If you do, > > you will practically never go into C3. What does > > > > sysctl dev.cpu | grep cx_usage > > > > say? > > > > Hi, > > My laptop reports C1 state only: > > $ sysctl -a | grep cx_ > hw.acpi.cpu.cx_lowest: C1 > dev.cpu.0.cx_supported: C1/1 > dev.cpu.0.cx_lowest: C1 > dev.cpu.0.cx_usage: 100.00% > > But this is Pentium-M and I remember it could use C2 and C3 back with > 5.x kernel and I'm sure I had USB as I have now. > > Do you have any idea why I don't have C2/C3 states available anymore ?? Under 7-Stable, my Pentium-M system (ThinkPad T43) shows C1, C2, and C3. Of course, it's not an SMP. dev.cpu.0.cx_supported: C1/1 C2/1 C3/85 dev.cpu.0.cx_lowest: C1 dev.cpu.0.cx_usage: 100.00% 0.00% 0.00% cx_supported has nothing to do with the value of cx_lowest. It should simply be what the CPU reports back vi ACPI as to the C states supported on the platform. -- 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_1227297434_96508P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) Comment: Exmh version 2.5 06/03/2002 iD8DBQFJJxKakn3rs5h7N1ERAnQyAJ48L9GUuEIOCB4luNeD3tQFZXXI7QCgn91Z vuxculU/7+ZBxQyjIS3UOIU= =uMO0 -----END PGP SIGNATURE----- --==_Exmh_1227297434_96508P--
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