A lot of us think this. The question is .. who's going to fix it? :-)
-adrian On 4 November 2013 09:52, Kevin Oberman <rkober...@gmail.com> wrote: > On Mon, Nov 4, 2013 at 12:46 AM, 李森 <lisen1...@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 to > 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 by > 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 for > 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=1 > hint.acpi_throttle.0.disabled=1 > > <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 the > most effective power management tools by default. > performance_cx_lowest="HIGH" # Online CPU idle state > economy_cx_lowest="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 other > than that, by default, FreeBSD tries to really, really hard to manage power > as badly as humanly possible. > </rant> > > -- > R. Kevin Oberman, Network Engineer > E-mail: rkober...@gmail.com > _______________________________________________ > firstname.lastname@example.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-acpi > To unsubscribe, send any mail to "freebsd-acpi-unsubscr...@freebsd.org" _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-acpi To unsubscribe, send any mail to "freebsd-acpi-unsubscr...@freebsd.org"