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Topic: speed differences between processor types (Read 4101 times) previous topic - next topic
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speed differences between processor types

I'm sure this is probably a simple question, but it really bothers me. I have a PC (550MHz) and a mac (400MHz) running os x (ppc-darwin). I have installed lame on os x using the usual ./configure, make, make install with the experimental compiler optimizations turned on (compiler=GCC 2.95) but only get speeds of 1.1x using --alt-preset fast standard. On my PC with the libs I get more than double the speed. Is the difference due to core routines being written in x86 assembly? And even with the assembly, does it really make that big a difference?

speed differences between processor types

Reply #1
Uhg...that is pretty nasty. I hope it's optimized sometime in the future for Mac.

speed differences between processor types

Reply #2
is there a way to "./configure" to make lame dual processor aware?

brett.

speed differences between processor types

Reply #3
Quote
Originally posted by brett
is there a way to "./configure" to make lame dual processor aware?

brett.


I wish :-) Been asking the same question but the answer seems to be no at the moment.

speed differences between processor types

Reply #4
i wonder if theres even x86 smp sual processor optimizations. i got a spare 2 x p2 300 comp running linux.

speed differences between processor types

Reply #5
LAME has no support for smp at all.

It shouldn't be impossible to implement this, but it might take a bit of work, and I don't know anyone who is particularly interested in doing this unfortunately.  I think it'd be cool myself though..

speed differences between processor types

Reply #6
Quote
Originally posted by c15zyx
I have a PC (550MHz) and a mac (400MHz) running os x (ppc-darwin). I have installed lame on os x using the usual ./configure, make, make install with the experimental compiler optimizations turned on (compiler=GCC 2.95) but only get speeds of 1.1x using --alt-preset fast standard. On my PC with the libs I get more than double the speed. Is the difference due to core routines being written in x86 assembly? And even with the assembly, does it really make that big a difference?


a) gcc floating point code (on ppc) is known to be 40% slower than codewarrior code.

b) altivec ppc asm code would speed up fft routines...

Best regards,

Wilfried

 
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