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Re: RFC: PCI SD host controller driver & mmc/mmcsd modules improvements

On Wed, 15 Oct 2008 23:25:11 +0300
Alexander Motin <mav_(_at_)_FreeBSD_(_dot_)_org> mentioned:
> Completely fortunate I have noticed that number of iterations depends on 
> my laptop power source. After small investigation I have found that it 
> actually depends on dev.cpu.0.freq value. With default value 2400 I have 
> only several iterations. But every double frequency decrease doubles 
> iteration count. With minimum value 100MHz I have more then 100 
> iterations. Same time it doesn't looks like this time is a real wall 
> time. It looks like DELAY() used in a loop has some problems with time 
> counting.

What do you mean? DELAY(9) on your laptop doesn't correspond to the
real time? AFAIK, DELAY(9) relies on current timecounter for time
accountiong, so there might be problems with it. Have you tried
switching the kern.timecounter.hardware sysctl to see if it will
affect results?

Stanislav Sedov

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