Date: Mon, 4 Nov 2013 10:00:48 -0800 From: Adrian Chadd <adrian@freebsd.org> To: Kevin Oberman <rkoberman@gmail.com> Cc: "freebsd-acpi@freebsd.org" <freebsd-acpi@freebsd.org>, =?UTF-8?B?5p2O5qOu?= <lisen1001@gmail.com> Subject: Re: Xeon E5 cpu work in low status Message-ID: <CAJ-Vmo=NznpPLxFrP7CKZtNmVwcgX7fvBWw98SNsP9iZ1PiRqg@mail.gmail.com> In-Reply-To: <CAN6yY1vyvmuN5UPzzoey4j1EEkgeKX0d62uL3MfhnPDdXCMB7g@mail.gmail.com> References: <CA%2BTSNq_9gGJrc3z_d-AJcqBKr164v5xYs5YRPJAeW_YED-Nb_w@mail.gmail.com> <CAN6yY1vyvmuN5UPzzoey4j1EEkgeKX0d62uL3MfhnPDdXCMB7g@mail.gmail.com>
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A lot of us think this. The question is .. who's going to fix it? :-) -adrian On 4 November 2013 09:52, Kevin Oberman <rkoberman@gmail.com> wrote: > On Mon, Nov 4, 2013 at 12:46 AM, =E6=9D=8E=E6=A3=AE <lisen1001@gmail.com>= wrote: > >> hi,all: >> the cpu of my machine is : Intel(R) Xeon(R) CPU E5-2643 0 @ >> 3.30GHz. >> >> after a reboot. The cpu freq is : sysctl dev.cpu.0.freq >> dev.cpu.0.freq: 1200 >> >> i didn't set any power savings config in rc.conf. >> >> How can i fix this? >> > > It's not clear what is broken. Is the server busy? Is there some reason t= o > expect it to be running at full clock-rate? > > What is the content of dev.cpu.0.freq_levels? > > By default, FreeBSD runs powerd and that will, by default, throttle back > the clock when the system is not busy. I think that this is a bad thing., > but it is not a bug. It's by design. I really think, based on my own > testing, research and a major NSF computer center (SDSC), and work done b= y > mav@ which can be found on the FreeBSD wiki ( > https://wiki.freebsd.org/TuningPowerConsumption), those "power management= " > tools are broken by design a they are actually there for thermal control, > not power management and are, at best, break-even, and in most cases are > actually a loser in both power savings and system performance. (There are= a > very few edge cases where they can be beneficial, but as a side effect fo= r > very specific loads under fairly unusual circumstances.) > > To turn off these (mis)features, add the following to /boot/loader.conf: > # Disable CPU throttling > hint.p4tcc.0.disabled=3D1 > hint.acpi_throttle.0.disabled=3D1 > > <rant> > All real power management is through the use of EST and CPU sleep (CX) > states. These can provide a big power win at minimal performance impact. > Unfortunately CX states and throttling lay very badly together, probably > because processor designers don't think that TCC and throttling are for > power management, so are not an issue. > > For reasons that have always baffled me, rather than disable the > inappropriate use of thermal management as power management, we disable t= he > most effective power management tools by default. > performance_cx_lowest=3D"HIGH" # Online CPU idle state > economy_cx_lowest=3D"HIGH" # Offline CPU idle state > > Even the comments are confusing: what do "Online" and "Offline" mean? > Offline means running on battery and online means AC power. > > In any case, it's not clear that there is any issue with your system othe= r > than that, by default, FreeBSD tries to really, really hard to manage pow= er > as badly as humanly possible. > </rant> > > -- > R. Kevin Oberman, Network Engineer > E-mail: rkoberman@gmail.com > _______________________________________________ > freebsd-acpi@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-acpi > To unsubscribe, send any mail to "freebsd-acpi-unsubscribe@freebsd.org"
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