[PD] tabread / write broken on 64bit AMD Linux

[Paris Treantafeles]

Hi Miller and List,

I can't resist asking (sorry if this is beating a dead horse) but...
I'm seriously considering building an AMD64 box for other purposes  
(e.g. cinelerra).
Given that, would it make sense to have two partitions?
One running Linux 64 bit (when using cinelerra) and the other a Linux  
32 bit for Pd, Gem, etc.?
Or are the concerns expressed below based on the processor more than  
the OS?

Thanks,
p

On Mar 25, 2006, at 1:53 PM, Miller Puckette wrote:

> The bad thing about 64 bit computing is that 64-bit programs tend to
> use more memory bandwidth than 32-bit ones, so that you would expect
> a processor to spend more time waiting for memory in 64 bit mode than
> 32.  This could easily outweigh the register-count advantage of AMD64
> in running Pd.  I'm planning to get an AMD64 box in another month  
> or so
> and should know more then... given the high prices of 64 bit machines,
> it might be smary to wait until we can get an actual speed comparison
> before spending the dough.
>
> cheers
> Miller
>
>
> On Sat, Mar 25, 2006 at 07:59:24AM +0000, carmen wrote:
>>> Well, I was going to do it, but we figured out that 64-bit wasn't  
>>> worth
>>> the trouble yet. It's not that much worth it until standard PCs  
>>> ship with
>>> well over 4G RAM.
>>
>> Ron Kuper sez 'no'... http://www.cakewalk.com/x64/whitepaper.asp
>>
>> " the CPU has twice the general purpose registers and twice the  
>> floating point unit (FPU) registers, compared to x86 processors.   
>> And each general purpose register is also twice as wide, 64 bits  
>> instead of 32 bits."
>>
>> "For a specific example of why this matters, consider a digital  
>> equalizer.  The math involved in computing equalization usually  
>> involves a processing element known as a "biquad".  A biquad is a  
>> small code fragment that manipulates 8 numeric values in a series  
>> of additions and multiplications.  The x86 floating point unit has  
>> a total of 8 registers, so even something as simple as 1 biquad  
>> will use up all of its registers. "
>>
>>> Apparently there are other advantages to the 64-bit
>>> mode, but I've not witnessed any difference with the programs  
>>> that I use.
>>> And then many programs' RAM usage might nearly double, especially  
>>> programs
>>> that use lots of pointers
>>
>> it is almost 2x, from what i recall, but having finally replaced  
>> the last Celeron here with a Sempron64, i can't double check..
>>
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