I think you're talking about several things at once. Katja's Pd Double is essentially about changing t_float to be a double-precision floating point number. But as I understand it she also revised the code in some of the core tilde classes like osc~ and phasor~ to optimize their performance. Those optimizations matter even if you compile her version of Pd to have a _single_ precision t_float. (I.e., with single-precision it will still outperform Pd Vanilla in her tests.)
That's a different issue than what happens when you run Pd on a 64-bit architecture. I don't understand how a 64-bit architecture would improve efficiency for math involving double-precision floats. Does it?
-Jonathan
On Sunday, February 1, 2015 11:52 PM, Alexandre Torres Porres <porres@gmail.com> wrote:
sure, but it still runs faster if compiled to 64 bits in a 64 bit OS, right?
why?
The only thing I have to back this assumption up is a recollection of a message by miller to the list saying that tests with the 64 bit version showed it was running faster, but I don't know anything about it, really. Still trying to learn from you. I'd also suspect that a double precision in Pd would make it much slower, but the benchmarks from Katja didn;t point this out. Seems like some future version of Pd running in full double precision is not too crazy, huh? cheers 2015-02-01 19:08 GMT-02:00 IOhannes m zmölnig zmoelnig@iem.at:
On 02/01/2015 06:05 PM, Alexandre Torres Porres wrote:
Seems Pd runs faster if compiled to 64 bits in a 64 bit OS than if it were compiled as 32, which does makes sense. That's all?
"*no : pd compiled for 64 bit system will not run on 32 bit sytem, and it will not load 32 bit externals.*"
sure, but it still runs faster if compiled to 64 bits in a 64 bit OS, right?
why?
if you run a 32bit binary on a 64bit OS, there might be some overhead involved (bit then i really don't know much about the performance of multi-arch systems)
if you run a 32bit binary on a 32bit OS on a 64bit CPU (x86_64, which is compatible with 32bit CPUs), then it might be slightly slower than compared to a full 64bit system.
the real advantages are:
- memory access!
a 32bit application/OS uses 32bit pointers to access memory. this limits the accessible memory to 4GB (your OS might be able to manage more using PAE; but the application itself will have a maximum of 4GB.) a 64bit application uses 64bit pointers to access memory. thats much more as you are likely to ever see in your lifetime (but then: 2640k are enough" anybody?)
- modern OSs are 64bit (even the not-so-modern w32[sic!] has started to
become a 64bit system). it seems silly to run 32bit applications on such systems (and a waste of ressources, as you need to install a 32bit version the entire runtime-environment)
also check out: http://en.wikipedia.org/wiki/64-bit_computing
fgrsam IOhannes
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