Date: Tue, 14 Jan 2003 19:16:39 -0800 From: Peter Wemm <peter@wemm.org> To: Josef Karthauser <joe@FreeBSD.org> Cc: Andrew Gallatin <gallatin@cs.duke.edu>, John Baldwin <jhb@FreeBSD.org>, Wilko Bulte <wkb@freebie.xs4all.nl>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, Nate Lawson <njl@FreeBSD.org> Subject: Re: cvs commit: src/sys/dev/acpica acpi_cpu.c Message-ID: <20030115031639.A88182A89E@canning.wemm.org> In-Reply-To: <20030115011342.GA5983@genius.tao.org.uk>
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Josef Karthauser wrote: > > --PNTmBPCT7hxwcZjr > Content-Type: text/plain; charset=us-ascii > Content-Disposition: inline > Content-Transfer-Encoding: quoted-printable > > On Tue, Jan 14, 2003 at 03:00:57PM -0800, Peter Wemm wrote: > > >=20 > > FWIW, we see a (measured) difference of about 50W on 2.2GHz P4's simply by > > turning machdep.cpu_idle_hlt on and off. I expect the clock throttling > > would make similar differences. For 1U rack-mount systems (especially in > > California) this is a Big Deal. > >=20 > > Which way's the way to reduce the power consumption? I would guess > 'machdep.cpu_idle_hlt=3D1', but as that appears to be the default I > thought I'd ask. Yes, it is the default, but for uniprocessor only. Sorry for not being clear. On SMP, machdep.cpu_idle_hlt=0 since we do not do resched IPI's to wake up the halted cpus, so this is a slight performance loss in mny cases. What I was trying to point out was that the power consumption of P4's varies a *HUGE* amount depending on what it is doing. Clock tweaking should have similar effects. > Joe > --=20 > Josef Karthauser (joe@tao.org.uk) http://www.josef-k.net/ > FreeBSD (cvs meister, admin and hacker) http://www.uk.FreeBSD.org/ > Physics Particle Theory (student) http://www.pact.cpes.sussex.ac.uk/ > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D An eclectic mix of fact an= > d theory. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > --PNTmBPCT7hxwcZjr > Content-Type: application/pgp-signature > Content-Disposition: inline > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.2.1 (FreeBSD) > > iEYEARECAAYFAj4ktcUACgkQXVIcjOaxUBYeLwCdEVgb4IjnDM0XTmH7cpcojQir > SfIAn2olNbW4mFQv8aXIRrWuXsA4t2bB > =TcBn > -----END PGP SIGNATURE----- > > --PNTmBPCT7hxwcZjr-- > Cheers, -Peter -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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