64 bit application, is it needed?

wumpus
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Topic 190772

Seeing as this question will come up in the future as more people get 64 bit hardware/OS combos. Could we create a sticky for this.

If the applications were to be coded for 64 bit, would we see any advantages or is the current E@H application fine as a 32 bit application.

Pooh Bear 27
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64 bit application, is it needed?

This has been answered several times, and the answer is on a 64bit OS, the 64 bit application will only give a 5-15% increase. The issue is the FPU has not significantly changed since the 32bit processor. Since all the calculations are run through the FPU, the only gain you get is the faster input/output of the processor when it needs to do things there.

wumpus
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IT being asked and answered

IT being asked and answered many time over is the point. Can it get created as a sticky and kept at the top? It really is asked a lot yet it doesn't appear in the FAQ's that I have noticed. I may just be nice to get an offical statement as to the plans of the community. Something along the lines,

We currently see no need to support more clients. When 98% of our worker bee/ drone platforms are ready we will consider it.

The Pirate
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The only real advantage is,

The only real advantage is, you can address more memory with 64 bit. If the applications were designed to use more that 4 gig you probably would see some improvement.


AMD-USR_JL
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RE: This has been answered

Message 25177 in response to message 25174

Quote:

This has been answered several times, and the answer is on a 64bit OS, the 64 bit application will only give a 5-15% increase. The issue is the FPU has not significantly changed since the 32bit processor. Since all the calculations are run through the FPU, the only gain you get is the faster input/output of the processor when it needs to do things there.


A 32 bit application in a 64 bit OS also slows down the application because the OS has to emulate a 32 bit OS to run the program. Also when the ps3 comes out the only way we will be able to harness its awesome crunching power would be to have a 64 bit einstein app. So maybe if Einstein was the only project with a 64 bit app, it would get all of the ps3's crunching power when it comes out. Spring in Asia, August/September in North America, and November/December in Europe(I think). The ps3's cell proccessor has an estimated 218 GFLOPS. Our overall floating speed right now is 36.7 TFLOPS, for each ps3 on Einstein it would raise it by .2 TFLOPS. I think that is pretty significant number for just one machine that only costs $500 US with the optional hdd.

DanNeely
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The PS3 only has truely wow

The PS3 only has truely wow levels of performance in single precision mode, and it's single precision FPUs are not true IEEE754 (the use the same data format but don't gaurantee the same level accuracy or precision). This means that they probably won't be precise enough for scientific use. For gaming purposes the 8th or 9th significant digit generally is irrelevant, scientific calculations need every last tiny ammount of it, and even very small errors in a single calculation will propagate significantly as the intermediate value is reused thousands or millions of times to compute the final result. All x86, powerpc, 68000, propriety risc, etc. (basically any general purpose cpu designed in the last 20(30?)ish+ years) is 754 compliant and will produce the same results for any given calculation.

This was not the case with older mainframes, and any old fogies can share stories about the fun that was had when a program ported across two different platforms, or even 2 versions of the same platform, produced completely different results. The problem was that speed and accuracy pull in different directions, and that improving one (while leaving the hardware level the same) will neccesary reduce the peroformance of the other. As I said, it's not an issue for gaming applications, where the last few digits are only needed to prevent truely wierd rounding, and deviations of 1/1000000 or even 1/1000 from the true result are meaningless.

I strongly doubt it'll be possible to harness the PS3s single precision FPUs for any scientific computations. Thier double precision units are 754 compliant but while good are not at the same mindblowing level as the single precision ones.

AMD-USR_JL
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Yea, but its double precision

Yea, but its double precision is about 25-30 GFLOPS. Its no where near its single of 256, but it is still very fast. My AMD athlon 64 x2 4800+ only has about 3.4 GFLOPS. At its lowest estimate of 25, it would be like having about 7 of my processors in one machine. In addition to all of this, there is growing number of people who have amd64 or itanium 64 processors, when the time comes to upgrade to vista many of them will want to upgrade to the 64-bit version. Like i said before since it has to emulate the 32 bit os to run the app it slows down, believe me because i have ran einstein in windows 64 bit it does slow down. So instead of a increase in time it takes to crunch you could have a decrease of 5-15% and utilize the cell.
You can read all about the cell's floating point capabilities hereunder "floating point capability."

m.mitch
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RE: The only real advantage

Message 25180 in response to message 25176

Quote:
The only real advantage is, you can address more memory with 64 bit. If the applications were designed to use more that 4 gig you probably would see some improvement.

Our beloved Microsoft will take care of that in no time!

m.mitch
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RE: ... [big snip]..... I

Message 25181 in response to message 25178

Quote:

... [big snip].....
I strongly doubt it'll be possible to harness the PS3s single precision FPUs for any scientific computations.
...[little snip].......

I don't know Dan, I looked at these Cell CPU's back when they were just starting to get publicity. The people behind them, IBM, etc. wouldn't invest that kind of money if they weren't going to be profitable.
Doing the first public release in a toy is not such a bad idea. No one will be bothered too much by any small inaccuracies. So clean ups can occur behind closed doors, unlike the Intel fiasco. CPU's that couldn't count, ha!
You might want do a search and see if all the original companies are still involved. I thought they looked like they were trying to break free of Intel on their small end stuff.

Jord
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RE: RE: The only real

Message 25182 in response to message 25180

Quote:
Quote:
The only real advantage is, you can address more memory with 64 bit. If the applications were designed to use more that 4 gig you probably would see some improvement.

Our beloved Microsoft will take care of that in no time!


Not if the hardware doesn't comply. The 64bit OS of Microsoft already adresses 2^64 of memory. It's just that the normal hardware can't do it yet. Your run of the mill motherboard can store at max 3.5 to 4GB. Don't try more. It won't work.
Not even with BIOS upgrades. You can't change the pathways that the extra memory can take with a simple BIOS update. You need new hardware. And about all of it.

Wurgl (speak^Wcrunching for Special: Off-Topic)
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RE: A 32 bit application in

Message 25183 in response to message 25177

Quote:
A 32 bit application in a 64 bit OS also slows down the application because the OS has to emulate a 32 bit OS to run the program.

This is not true for the x86_64 architecture. No emulation is needed, a 32 bit application runs as fast as one compiled for 64 bit.

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