Date: Wed, 11 Jan 2006 22:22:11 -0500 From: Mike Jakubik <mikej@rogers.com> To: Daniel O'Connor <doconnor@gsoft.com.au> Cc: stable@freebsd.org, freebsd-stable@freebsd.org Subject: Re: powerd effectiveness Message-ID: <43C5CB63.7060202@rogers.com> In-Reply-To: <200601121326.18384.doconnor@gsoft.com.au> References: <43C5A261.1020407@rogers.com> <200601121326.18384.doconnor@gsoft.com.au>
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Daniel O'Connor wrote: > On Thu, 12 Jan 2006 10:57, Mike Jakubik wrote: > >> It seems that powerd does very little in terms of reducing heat, and >> sacrifices performance while doing so. Am i wrong to assume that >> lowering the cpu's frequency should reduce consumed power, and therefore >> reduce the amount of heat produced? I have tested with mbmon and i see >> no difference between an idle system running with powerd at 75mhz, and >> at full rate without. Also, while testing the speed of a php script, i >> > > If you want to test how much heat your system draws for a given clock speed > you should dispense with powerd and just set the frequency by hand, ie.. > > sysctl dev.cpu.0.freq=XXX > > powerd won't run your CPU at a specific clock frequency - it varies the CPU > frequency based on current load conditions. > > The load was 0, only thing that was running was mbmon. > Do you have thermally controlled fans? If so I wouldn't expect the temperature > to vary with clock speed very much at all. > > No, i do not. > The powerd defaults do not change frequency that quickly - every 500ms by > default. I run it with '-p 200' and it seems fine although you do notice it > 'stick' sometimes (where the CPU change doesn't happen quickly enough). > > You could try what I do but there are some systems which are very slow to > change clock speed so this could be an impediment. > What was part of my question, is it the hardware or the software thats at fault here. I.e. would a cool n quiet system be better.
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