Date: Tue, 6 Jun 2006 11:40:31 +0530 From: "Joseph Koshy" <joseph.koshy@gmail.com> To: "Paul Lipps" <paul.lipps@gmail.com> Cc: freebsd-smp@freebsd.org Subject: Re: High Pitched Whine Message-ID: <84dead720606052310s62ad2a5dt884fce4dd192b05d@mail.gmail.com> In-Reply-To: <988CE3F0-B4FB-40B3-AE6E-C079E54BD290@gmail.com> References: <988CE3F0-B4FB-40B3-AE6E-C079E54BD290@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> When I am running FreeBSD, my computer emits a high pitched > whining noise. It's not a 'physical' noise like a fan or hard > disk grinding, it's more of a electrical whine. The only thing that I can think of that could think of that could whine is a flaky magnetic component. Does the frequency of the whine change if you change HZ? Does the whine reduce if the processor is fully compute bound? On an idle system, the processor should quickly go back to sleep after handling the clock interrupt. Since this should take a few uSecs at most, the processor's power requirement surge should be handled by the reserves in the power supply's output capacitors. My guess is that FreeBSD's clock handling is taking long enough that your SMPS needs to (briefly) increase its current output. This change in current output could cause a whine if a magnetic coil in the SMPS was loose. Someone with a spare 'scope could check this hypothesis out ... if there's a correlation between the ripple on the 5V line and the clock rate on an otherwise idle system, then we're spending too many cycles in our clock handler. -- FreeBSD Volunteer, http://people.freebsd.org/~jkoshy
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?84dead720606052310s62ad2a5dt884fce4dd192b05d>