Date: Sun, 23 Oct 2005 11:03:52 -0700 From: Nate Lawson <nate@root.org> To: Alexander Leidinger <Alexander@Leidinger.net> Cc: current@freebsd.org Subject: Re: 1kHz noise from C3 sleep Message-ID: <435BD088.30205@root.org> In-Reply-To: <20051023121338.3e253c97@Magellan.Leidinger.net> References: <200510172310.j9HNAVPL013057@repoman.freebsd.org> <20051018094402.A29138@grasshopper.cs.duke.edu> <435501B9.4070401@samsco.org> <43553162.5040802@root.org> <20051020141023.0ejwdv4dss48wko0@netchild.homeip.net> <4357E137.5090703@root.org> <20051023121338.3e253c97@Magellan.Leidinger.net>
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Alexander Leidinger wrote: > On Thu, 20 Oct 2005 11:25:59 -0700 > Nate Lawson <nate@root.org> wrote: > > >>Alexander Leidinger wrote: >> >>>Nate Lawson <nate@root.org> wrote: >>> >>>[Moving to -current] >>> >>> >>>>>I wonder if moving to HZ=1000 on amd64 and i386 was really all that good >>>>>of an idea. Having preemption in the kernel means that ithreads can run >>>>>right away instead of having to wait for a tick, and various fixes to >>>>>4BSD in the past year have eliminated bugs that would make the CPU wait >>>>>for up to a tick to schedule a thread. So all we're getting now is a >>>>>10x increase in scheduler overhead, including reading the timecounters. >>>> >>>> >>>>I use hz=100 on my systems due to the 1 khz noise from C3 sleep. >>>>Windows has the same problem. >>> >>> >>>My laptop makes noises when being (more or less) idle (I think I enabled >>>C3...). Does this mean I should try to change HZ? >> >>Sure, you can do it from a tunable (kern.hz I think), you don't have to >>recompile. > > > No, a HZ of 100 doesn't work, the laptop still makes noises. And it > only has C2, no C3... Change to C1 (which is just HLT). If it still makes noise, it's not your C2 or C3 sleep. -- Nate
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