Full 64 bit optimization
When do you guys think that OS X will get full 64 bit optimization? I realize that for quite a while it will have to have FAT code much in the same way 16 bit code coexisted with 32 PPC code for some time.
Do you think that full optimization could bring significant performance gains?
Anywho, just my musings. Hope this hasnt already been discussed...
Do you think that full optimization could bring significant performance gains?
Anywho, just my musings. Hope this hasnt already been discussed...
Comments
Originally posted by 4fx
When do you guys think that OS X will get full 64 bit optimization? I realize that for quite a while it will have to have FAT code much in the same way 16 bit code coexisted with 32 PPC code for some time.
Do you think that full optimization could bring significant performance gains?
Anywho, just my musings. Hope this hasnt already been discussed...
Fat binaries had nothing to do with 16-bit code. It had to do with code for the 680x0 processor and the PowerPC. Both are 32-bit chips. Macs have been 32-bit clean since the Mac IIci. Fat binaries are still with us in the Classic environment and in all Classic applications. That is because the Toolbox ROM (and ROM file) was never completely ported to PPC.
As for 64-bit code, it bears repeating that the PowerPC was a single chip implementation of the POWER chip set. The POWER ISA was 64-bit. The differences among the ISAs in the 32-bit PPCs and the 64-bit ones are vanishingly small--just a few instructions. You find more variation in other processor families of a single bit-ness. The G5 runs 32-bit MacOS X 10.2.7 and its 32-bit applications natively. No emulation is required.
Originally posted by 4fx
I realize that the G5 will run 32 bit code natively, but isnt there an advantage of having 64 bit code? Otherwise what would be the point in having a 64 bit processor?
As has been said many times before, a 64-bit processor can access more memory than a 32-bit processor. It can also manipulate larger precision numbers with a single instruction. If you need to address more memory or to manipulate larger precision numbers, then 64-bit processors have a definite advantage. If your don't, then a 64-bit processor will be a wash, at best.
It will come in time, when all curents hardware released by Apple will have 64 bits CPU. It won't come until two of three years.
Originally posted by Powerdoc
A full 64 bit optimization will boost the OS X interface certainly. A 64 bit disk file system will be a big improvement for giants HD.
It will come in time, when all curents hardware released by Apple will have 64 bits CPU. It won't come until two of three years.
Oh fiddle sticks... now I have to add to the list of things to wait for with my fingers crossed...
1. Quantum Computing... 10 to 100 years.
2. Living on Mars... 20 to 30 years.
3. G5 PowerBook... in a year.
4. Full 64-bit OSX... 2 to 3 years.
64-bit support for the applications that need it is plenty. It's not like there are all that many applications that need it. Apple has time to do it right before 32 bit computing becomes a bottleneck even at the pro level, and even then there'll be plenty of room for 32 bit libraries and applications.
There's also nothing stopping a 32 bit CPU from running a 64 bit filesystem. There's a performance hit, but it vanishes in the tremendous number of cycles the CPU spends waiting for the hard drive.
Originally posted by Amorph
Why is everyone so hung up on a "full 64 bit OS" anyway?
Apple created this problem for themselves.
Apple: "First 64-bit personal computer!"
Users: "So when do we get full native 64-bit support?"
It's confusing to say "you don't need 64-bit right now" and "woohoo we have 64-bit and you Windows weenies don't nya nya nya" at the same time.
Originally posted by Amorph
Why is everyone so hung up on a "full 64 bit OS" anyway?
You could ask the same thing about megahertz... and get the same answers.
Originally posted by 4fx
When do you guys think that OS X will get full 64 bit optimization?
There is no "64-bit optimization". 10.3 is optimized for the PPC970, but that is different than "64-bit optimizations".
There are a two basic 64-bit capabilities: 64-bit math and 64-bit memory. OSX already supports 64-bit math. The 64-bit memory will take longer, and for me this is the really interesting part of going 64-bit... even without >4 GB of physical memory installed. But I'm a programmer and the things I want this for are rather esoteric. For the typical user there is no benefit to 64-bit memory.
Some day, maybe in a few months or years, 64-bit will be the requirement. IBM or its replacement will come out with a 128 bit chip. Someone will say, "when is apple going to make everything 128 bit?" and people will respond, "we don't need that. its superfluous, aside from giving us huge amounts of memory." i, for one, welcome our huge bitted overloads. viva la revoluction.
Originally posted by thuh Freak
It's short-sighted to say that most programming will halt at 32-bit, and merly use the extra space for memory. Technology doesn't stop. It's like a virus.
What you need to undestand is that programmers have been doing computations with 64-bit and higher precisions all along. There wasn't some unsurmountable barrier to doing 64-bit computations before the G5 came along. Applications that benefit from 64-bit computations are already doing 64-bit computations. On the G5 they will run faster, but that is all.
The higher precisions are used where they make sense and avoided where they don't make sense. There is a price to pay for doing 64-bit computations. The 64-bit data and address variables take twice the memory as 32-bit data and address variables. Using variables with more precision than needed for the job at hand is a waste of memory and can reduce performance, even on a G5.
Think of our 64bit platform as a truck with a trailer hitch. You should only attach a trailer (write 64bit code) when you need to haul that much stuff (data). Otherwise, performance will actually suffer so drive around without the trailer (in 32bit mode).
Of more significance is the state of OS X's PPC970 optimization...
Originally posted by spooky
Does 64 bit not help with rendering 3D or video files?
It can help with video production, and I assume 3D as well.
Originally posted by spooky
Does 64 bit not help with rendering 3D or video files?
It depends on what you mean by "help". If you mean make rendering faster, then the answer is no in most cases I can think of. In fact I can think of many cases where using 64-bit values instead of 32-bit ones will slow things down, even on a G5.
Originally posted by Tidris
In fact I can think of many cases where using 64-bit values instead of 32-bit ones will slow things down, even on a G5.
care to explain this bit? a 64bit proc like the g5 will natively handle 64bitness. doing anything else would (in theory) present slowdowns, i would think.
Originally posted by thuh Freak
a 64bit proc like the g5 will natively handle 64bitness. doing anything else would (in theory) present slowdowns, i would think.
The G5 does not slow down when doing 32-bit computations. AFAIK computations on 32-bit data take the same number of CPU cycles as computations on 64-bit data once the data has been loaded into CPU registers. However, with 64-bit computations you have twice as much data to move between CPU, caches, and main memory, and moving extra data around takes extra time. In addition, if your data has 64 bits of precision then AltiVec can't help you nearly as much as when your data has 32 bits of precision. The highest precision that AltiVec can handle directly is 32-bit integer and 32-bit floating point.