fujiwara@f.pyon.org wrote:

> [ ... ]
>
> and I tested 3 frequencies.
> 
> $ sysctl -w machdep.est.frequency.target=800
> 
> type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
> md2                547.04k     1171.23k     1639.73k     1820.31k     1880.71k
> 
> $ sysctl -w machdep.est.frequency.target=700
> 
> type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
> md2                410.36k      878.45k     1229.66k     1365.11k     1410.44k
> 
> $ sysctl -w machdep.est.frequency.target=600
> 
> type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
> md2                409.26k      878.38k     1229.97k     1365.14k     1410.43k
> 
> 700MHz and 600MHz are the same and
> it is 75% of 800MHz performance.
> 
> Does this CPU have 700MHz mode?

Your tests should that it doesn't, which is annoying since there's two
other CPUs listed in sys/arch/x86/x86/est.c that have constant mV but
have more than two frequencies available.

It looks like the safest thing to do is just use the lo and hi
frequencies for the case where the voltage is the same.

Cheers,
Simon.