Date: Thu, 05 Apr 2012 20:47:02 +0300 From: Volodymyr Kostyrko <c.kworr@gmail.com> To: =?UTF-8?B?0JvRjtCx0L7QvNC40YAg0JPRgNC40LPQvtGA0L7Qsg==?= <nm.knife@gmail.com> Cc: Ivan Klymenko <fidaj@ukr.net>, freebsd-stable@freebsd.org Subject: Re: lowest C-state changes Message-ID: <4F7DDA96.4010305@gmail.com> In-Reply-To: <CAHi1JscsVbGNcqaZZ78xpCXoGh%2BYK7b2SOJmSK=O=Xpfvniniw@mail.gmail.com> References: <CAHi1Jscju7t1PdZa7yjY6kKK0tAuqwc8GUidO3e8o=P__BybQA@mail.gmail.com> <4F7D70C7.60105@gmail.com> <4f7d73db.96e7d80a.509c.2afaSMTPIN_ADDED@mx.google.com> <CAHi1JscsVbGNcqaZZ78xpCXoGh%2BYK7b2SOJmSK=O=Xpfvniniw@mail.gmail.com>
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=D0=9B=D1=8E=D0=B1=D0=BE=D0=BC=D0=B8=D1=80 =D0=93=D1=80=D0=B8=D0=B3=D0=BE= =D1=80=D0=BE=D0=B2 wrote: > > Have you checked http://wiki.freebsd.org/TuningPowerConsumption? > I have. It was kind of confusing and didn't know about: > > 1. For CX states to function correctly you better disable throttling= > > and powerd. I also witnessed at least one machine that hitting any C= X > > mode stops generate interrupts on APIC clock (I had to boot it with = a > > mousee until I disabled APIC clocks). > So do you recommend I use throttling or C3? I think C3 runs slightly > cooler. I can't tell since I don't drop under 50C in X. Fan increases a= t > 60C and drops me back. I wouldn't dare to recommend any particular configuration. Most times=20 throttling is safer and with CX states you can get cooler. But both of=20 them doesn't play nice together. If you want higher cooling you can try=20 to disable throttling (and you will not need powerd as powerd takes care = of frequencies) and enable CX but you will need to test everything=20 thoroughly as unepected bugs can show up. Remember, the default way=20 isn't the better one, just the safer one. > > First need to see what state the processor supports the current > > system > >sysctl -a | grep cx_ > This is before heavy load while it still remembers the C3: It's just about ability to set C3 or any other particular state. Some=20 processors show only C1 state as available. For example: > sysctl hw.model hw.model: Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz > sysctl dev.cpu | grep cx dev.cpu.0.cx_supported: C1/1 dev.cpu.0.cx_lowest: C1 dev.cpu.0.cx_usage: 100.00% last 293us dev.cpu.1.cx_supported: C1/1 dev.cpu.1.cx_lowest: C1 dev.cpu.1.cx_usage: 100.00% last 15us Setting lower CX on this machine results in: # sysctl hw.acpi.cpu.cx_lowest=3DC3 hw.acpi.cpu.cx_lowest: C1 sysctl: hw.acpi.cpu.cx_lowest: Invalid argument --=20 Sphinx of black quartz judge my vow.
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