OESF Portables Forum

Everything Else => Zaurus - Everything Development => Distros, Development, and Model Specific Forums => Archived Forums => User Request for Applications => Topic started by: Neo-Rio on October 14, 2005, 11:56:26 am

Title: Speeding Up Compiles
Post by: Neo-Rio on October 14, 2005, 11:56:26 am
I just finished compiling VICE, the Commodore 64 emulator for my SL-C3000

However, the thing runs painfully slow (actually, so does PrBoom but at least that is playable)

What do I do to make compiled programs run faster. Are there any special optimizations that I can do during configure ? I am running the Sharp original ROM with Qtopia as I got the machine. Will putting in a new ROM speed things up - the screen refresh on the Zaurus seems sluggish.
Title: Speeding Up Compiles
Post by: qx773 on October 15, 2005, 09:06:29 am
Perhaps you could try the C compiler options -O2 -s to make the compiler perform some optimizations, but not too much, and strip debugging information from the output executable program to make it smaller.  Higher levels of optimization can actually cause a program to run slower by increasing the program size, due to loop unrolling, function inlining, and other size-increasing optimizations, causing code to overflow the instruction cache.  I am not sure if -s will have any effect on the execution speed, but it will at least make the executable program occupy less disk space / flash memory space.
Title: Speeding Up Compiles
Post by: Neo-Rio on October 16, 2005, 10:10:07 pm
Quote
Perhaps you could try the C compiler options -O2 -s to make the compiler perform some optimizations, but not too much, and strip debugging information from the output executable program to make it smaller.  Higher levels of optimization can actually cause a program to run slower by increasing the program size, due to loop unrolling, function inlining, and other size-increasing optimizations, causing code to overflow the instruction cache.  I am not sure if -s will have any effect on the execution speed, but it will at least make the executable program occupy less disk space / flash memory space.
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Thanks for the tips.

I compiled it originally at -O2, so I ratcheted it up a bit to -O5, but that was too much, so I dropped it back down to -O3, which seemed to work a little bit better but not much. That -s really helped shrink the ipk too. Thanks

Unfortunately I don't think VICE is ever going to run full speed on the SL-C3000. Commodore 64 emulators require a lot of horsepower to get the video timings exact, and unfortunately I think a StrongArm is required, rather than a 416Mhz xscale - already burdened with Qtopia and X/Qt

*sigh*