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Re: nacl and CPU frequency.

On Sat, Sep 22, 2012 at 05:29:45PM +0100, peter green wrote:
> I therefore conclude that if it's not returning elapsed times in true CPU
> cycles it probablly doesn't matter much if the supposed CPU speed and the
> real CPU speed are not exactly the same.
> As such unless someone objects I plan to patch the code to fallback to
> using bogomips as a "psuedo CPU speed" if true CPU speed cannot be
> determined.
procps has been struggling with this for years, though ita mainly around
the CPU ticks versus real seconds.  If you are really bored, have a look
at some old procps bugs where this sort of thing has broken.

We've narrowed it down to a small handful of checks. The real value is
probably unknown for some devices so we just set it to a fixed value.

The point is, trying to guess this sort of stuff will probably give you
the wrong number so a "pseduo CPU speed" is probably as bad as anything
else you can come up with, so find something simple.

 - Craig
Craig Small VK2XLZ   http://enc.com.au/          csmall at : enc.com.au
Debian GNU/Linux     http://www.debian.org/      csmall at : debian.org
GPG fingerprint:     5D2F B320 B825 D939 04D2  0519 3938 F96B DF50 FEA5

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