Re: Stealing ur megahurts (no, really)

From: Dr. David Alan Gilbert
Date: Fri May 19 2006 - 07:22:30 EST

* John Richard Moser (nigelenki@xxxxxxxxxxx) wrote:

> Scrambling for an old machine is ridiculous. Down-clocking makes sense
> because you can adjust to varied levels; but it's difficult and usually
> infeasible. Pulling memory and mix and matching is not much better.


> This brings the idea of a cpumhz= parameter to adjust CPU clock rate.
> Obviously we can't do this directly, as convenient as this would be; but
> the idea warrants some thought, and some thought I gave it. What I came
> up with was simple: Adjust time slice length and place a delay between
> time slices so they're evenly spaced.


Hi John,
While cpu downclocking helps a bit, it would be hopelessly inaccurate
for figuring out if your app would run fast enough on the given
ancient machine. A lot else has happened to the world since the days
of the 200MHz CPU:
* Faster memory
* Larger caches
* Faster PCI busses
* Instruction set additions (various more levels of SSE etc)
* Faster discs
* Changes to the CPU architecture/implementation

Still, it would be interesting to see the difference in performance
of a downclocked modern processor and its 10 year old clock equivalent.


-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux on Alpha,68K| Happy \
\ gro.gilbert @ | MIPS,x86,ARM,SPARC,PPC & HPPA | In Hex /
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