82xx performance

[Rune Torgersen]

> 9919_unit  Linux 2.6.25       powerpc-linux-gnu  434    32    32  
> > 1.0000 1
> > 9919_unit  Linux 2.6.18       powerpc-linux-gnu  445    32    32  
> > 1.0100 1
> 
> Hmm, processor MHz is off by 11/445

I noticed that.

> And memory latency is off 13/500.
> 
> That sounds like it will be 16/666.
> 
> Are you using the same board and the same firmware?

Yes. Same board, same firmware, same filesystem, just booted with
different kernels.

> 
> If so, look at /proc/cpuinfo and/or the boot log to see what
> frequency linux thinks the processor is running at.  It sounds
> like someone introduced or fixed a rounding error error calculating
> the timebase frequency for your board.

2.6.18 /proc/cpuinfo
processor       : 0
cpu             : G2_LE
revision        : 1.4 (pvr 8082 2014)
bogomips        : 296.96
chipset         : 8250
vendor          : Innovative Systems LLC
machine         : AP Gold

mem size                : 0x40000000
console baud            : 115200

core clock      : 447 MHz
CPM  clock      : 298 MHz
bus  clock      : 99 MHz


2.6.25 /proc/cpuinfo
processor       : 0
cpu             : G2_LE
clock           : 447.897600MHz
revision        : 1.4 (pvr 8082 2014)
bogomips        : 49.53
timebase        : 24883200
platform        : Innovative Systems ApMax


> Please try the sleep test: sleep for 100 seconds, and time with
> either a stopwatch or another system.  I think you will find they
> take different amounts of time, and all the results need to be scaled.
> You might be able to see it reading the hardware clock.

Sleep 100 takes excactly 100 seconds on both kernels (verified with
stopwatch and external ntp server)