forums.ps2dev.org

[skeezixcodejedi]

I realize this is top of the flamebait, but its also something that needs to be nailed down good for everyone.. I did some searches and found numerous recommendations but not a concrete 'this is likely your best bet'. Please let me know if this is noted somewhere so I don't waste your time ;)

For instance.. I noticed a slowdown when I turned on some code that more or less boils down to "sceCtrlReadBufferPositive", so that may be a chokepoint (though it could be a few other things so I'm not saying for sure just yet.) In this case, rather than checking every 'frame' (its an emulator here), I'll check for inputs every couple frames to reduce the cost..

For fun, I cribbed some of the gcc optim flags I use in ARM code:
CFLAGS = -G0 -Wall -O2 -x none -msingle-float -funroll-loops -ffast-math -fsingle-precision-constant -ffunction-sections -fexpensive-optimizations -finline-functions -fomit-frame-pointer -ffast-math

(This is a subset; I use a tonne of ARM-specific optims there.)

Likewise, I'm turning the PSP clock up to 333; is this done correctly? Do I need to muck with the bus speeds or subsystem speeds at all? (I admit here, all I did was look in psppower.h for the first thing that sounded good ;)

scePowerSetCpuClockFrequency ( 333 );

Pound for pound, how well does the MIPS4000 (or whatever we've got here) rate to a similar ARM chip? ie: If we're running at 333MHz here, should it compare to a 300MHz ARM runtime? (ie: Pure computation, GPU aside.)

No need to go into logic code changes here; just 'out of band' things to set that can improve runtime speed.

Many thanks!

jeff
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