Nice discussion! ;-)

Would anybody of you be willing to actually have a look on the Rosetta source and make an educated guess whether optimizing for 64 BIT (and for SSE etc.) could lead to a significant performance gain? That might soon be possible. If yes, please email me: joachim@iwanuschka.de

regards

Joachim

@Brian Bowles:
That's normal. With the normal settings, BOINC (Rosetta) uses the free CPU cycles. When you are typing a letter in Word, or surfing the internet, it uses less than 5% of your CPU power. The project (Rosetta) uses the free CPU cycles.
This is the way the DC program works.

The application runs at the lowest priority. This means that when another application asks more CPU power (example: you start up graphical software), this application gets this immidiatly. So for example your normal work asks at that moment 75% of your CPU, Rosetta only gets the rest (25%).
A few moments later, your normal work asks 15%, boinc gets 85%.
So Rosetta has the lowest priority: it only gets what isn't being used by other applications.

From a general standpoint, the "bitness" of the application does not equate to performance improvement or degredation. The thing that really matters is the source code, compiler/assembler, and linker taking advantage of the architecture. In some cases, 64-bit will not be faster or slower, but could take up almost twice the memory footprint. Only the developers, who have access to the source code and higher-level algorithms and know how to work with the architecture can tell if an application will see significant improvements.

the "bitness" of a application does not equate to performance improvment or degredation - is incorrect, because you are setting a inflexible rule that can be proved incorrect with:

// Passing values to a function.
mov rax, [offset FunctionArg2]
mov eax, [offset FunctionArg1]
// I want to pass two values to a function.
mov rax, ecx
shl rax, 32
mov eax, edx

Just because a register is considered a whole object does not mean you can not manipulate it to store more information while keeping the information seperate. People, think oh a 64 bit register... hmm I will never store a value over a 32 bit limit oh well no use for the extra 32 bits.. =

You know I still can not understand how everyone rants and raves, about why not make a 64bit version. Yet the only reply is can we really use quad word registers, and over 4 gigabytes of memory.

Its almost like there is a stigma associated with a 64bit processor, only being good for having 32 extra bits for processing power?

Does anyone know, or has anyone who did know forgotton that a 64 chip has 8 more general purposes registers. This means almost all functions calls that use integral data types can make their calls with out placing arguments onto the stack.

It also means fewer RAM reads/writes, and any value in a register has almost instant access for read/write by the processor.

A 32bit processor can provide 32 bytes at most, using all its general purpose registers.

A 64bit processor can provide 64 bytes with no loss of flexibility due to register usage, plus the original 8 registers that also provide 64 bytes of total space.

Thats 32 bytes vs 128 bytes, thats four times larger, while making irelavant the fact that Rosetta@Home only uses single percision 32 bit floating point values, and less than 2 gigabytes of memory.- who cares? That has to be a performance gain.


I know there has been lots of discussions regarding this, and even the fact that some say there is no performance gain. I have even read that a application got slower? Who did the benchmarking, and I want to see the source code because something was not done correctly! It should at least equal the 32 bit version, but never fall to half the speed even if the port does not take advantage of any 64 bit features! Thats just plain and simple logic.. Someone is talking alot of bull. I mean at least post some references to some technical information about why it was slower. If you do not know why you do not know if it is being done correctly(porting).

I checked ralph@home, and did a quick search of the site using google, and this site and only found a small remark about releasing the source code and that was it?