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Raspberry Pi's GPU double the performance of iPhone 4S

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Re: Raspberry Pi's GPU double the performance of iPhone 4S

#51

Post by jules »

theatrus2 wrote: post #50
jules wrote: post #28

Earlier quoted context omitted.

I wonder when mobile devices are going to contain FPGAs. They are often a factor of 100x power/performance better than CPUs/GPUs.

FPGAs are typically 5-20x worse in power consumption and max speed over a dedicated ASIC with the same logic. That is the price you pay for flexibility of being able to change your design at the drop of a hat. For now, they are the low volume option (<1-10m units) if you need special interfaces. If all you are doing is number crunching a Gpgu would likely be a more effective option.

While superb for power and performance, the problem with ASICs is that you can't embed an ASIC fab in your mobile phone ;) On the other hand, doing number crunching on a GPU will quickly burn your your battery. FPGAs seem like the ideal middle ground.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#52

Post by jules »

pavlov wrote: post #36
jules wrote: post #28

Earlier quoted context omitted.

I wonder when mobile devices are going to contain FPGAs. They are often a factor of 100x power/performance better than CPUs/GPUs.

Can you provide some examples where an FPGA provides such performance gains over a modern CPU and GPU combo?

Microsoft Research has some papers on this, for example:

Where’s the Beef? Why FPGAs Are So Fast -- http://research.microsoft.com/pubs/70636/tr-2008-130.pdf

BLAS Comparison on FPGA, CPU and GPU -- http://research.microsoft.com/pubs/130834/ISVLSI_FINAL.pdf

"Results show that FPGAs offer comparable performance as well as 2.7 to 293 times better energy efficiency for the test cases that we implemented on all three platforms."

Here's a talk about compiling legacy C/C++ code to FPGAs. With a couple of modifications to the code they claim 100x-300x performance/watt improvement in various benchmarks.

slides: http://msrvideo.vo.msecnd.net/rmcvideos/103696/dl/103696.pdf

video: http://research.microsoft.com/apps/video/default.aspx?id=103...

For example they have a Black Scholes simulation that runs 30x faster and uses 6W of power instead of 68W. That's >300x power efficiency.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#54

Post by easp »

bockris wrote: post #27
pbhjpbhj wrote: post #15

Earlier quoted context omitted.

>"The 256 MB of RAM will be very constraining for any app trying to use all that power, though." My Archos 101 has 256MB RAM and runs Android suprisingly well. It only does 720p video playback though; full specs http://www.archos.com/products/ta/archos_101it/specs.html?co... . I'm not going to lie, it does tend to lag a bit; wonder how easy upgrading the RAM will be on the RPi.

The RasberryPi is using a BCM2835 SoC that has the RAM on the die. Basically not upgradeable without swapping out the whole chip. http://en.wikipedia.org/wiki/Raspberry_Pi

The RAM isn't on the die, it is in a package that gets stacked on top of the SoC package. Still not going to be a simple upgrade though.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#56

Post by luser001 »

sern wrote: post #29
NickPollard wrote: post #25

Earlier quoted context omitted.

Whilst I would certainly agree it would be nice for the chip to be open-sourced, saying that it means the Pi is 'already dead' is ridiculous hyperbole. The Raspberry Pi is designed for computer science education, but it's designed primarily for Children , not University Students. If you're at the point of running 'Advanced Operating Systems' courses then you can find whatever you need, but 12 year olds aren't likely…

They absolutely don't need special hardware to start programming. I'm sure I'm not alone in saying that my first exposure to coding was when I typed "10 PRINT BUTT 20 GOTO 10" into BBC BASIC. I didn't need anything more than the computer I had at school. The modern-day equivalent - typing "python" into the terminal - isn't much different, and still a lot easier and cheaper than getting something to run on an external…

This IS today's version of the BBC Micro. AFAIK, the BBC Micro was a cheap design to encourage computer education since regular PCs were very expensive.

I too cut my teeth on a BBC Micro. My school had ~20 of them. If they'd bought PCs, they would have had maybe 5?

The Raspberry Pi will do the same thing today, especially in poor countries which don't have computers as a matter of course in their schools.

You're talking from an overly Western-centric perspective when you say that typing "python" is cheaper than the RPI.

The world has 7 billion people, many of whom live in poor countries. At $35 with the ability to use a regular TV as a console, this thing is well within the reach of poor person even in a poor country like India to buy as a splurge for his kid who he's told my their teacher is bright.

I, for one, think this is going to be revolutionary.

PS: I also plan to use it for some home automation projects. It can run off of batteries (!!!!!), and is a plain old GNU/Linux distro. How cool is that.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#57

Post by nirvana »

It seems to me that they're comparing a USB powered device to a battery powered device.

The iPhone runs its GPU in a particular way, and its GPU was chosen based on the fact that the iPhone needs to have its battery last all day.

However the Raspberry can draw a continuous 1A without rest, because it effectively has an infinite battery.

So, sure, you can put a larger GPU in a device like that.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#58

Post by sern »

luser001 wrote: post #56
sern wrote: post #29

Earlier quoted context omitted.

They absolutely don't need special hardware to start programming. I'm sure I'm not alone in saying that my first exposure to coding was when I typed "10 PRINT BUTT 20 GOTO 10" into BBC BASIC. I didn't need anything more than the computer I had at school. The modern-day equivalent - typing "python" into the terminal - isn't much different, and still a lot easier and cheaper than getting something to run on an external…

This IS today's version of the BBC Micro. AFAIK, the BBC Micro was a cheap design to encourage computer education since regular PCs were very expensive. I too cut my teeth on a BBC Micro. My school had ~20 of them. If they'd bought PCs, they would have had maybe 5? The Raspberry Pi will do the same thing today, especially in poor countries which don't have computers as a matter of course in their schools. You're talk…

The BBC Micro was actually quite expensive compared to the other micros of the time. (I don't think the IBM PC was ever considered a "micro", and other micros were probably more capable anyway.) If I remember correctly, the goal was not to produce a design that would compete mostly on cost but rather one that was British and would do the flashy stuff the BBC wanted to show on their computing series.

I agree that the Raspberry Pi will be revolutionary, not because it will rejuvenate computer science teaching, but simply rather because it's a cheap computer.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#59

Post by pbhjpbhj »

bockris wrote: post #27
pbhjpbhj wrote: post #15

Earlier quoted context omitted.

>"The 256 MB of RAM will be very constraining for any app trying to use all that power, though." My Archos 101 has 256MB RAM and runs Android suprisingly well. It only does 720p video playback though; full specs http://www.archos.com/products/ta/archos_101it/specs.html?co... . I'm not going to lie, it does tend to lag a bit; wonder how easy upgrading the RAM will be on the RPi.

The RasberryPi is using a BCM2835 SoC that has the RAM on the die. Basically not upgradeable without swapping out the whole chip. http://en.wikipedia.org/wiki/Raspberry_Pi

Sounds just like the Archos RAM limitation.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#60

Post by luser001 »

sern wrote: post #58
luser001 wrote: post #56

Earlier quoted context omitted.

This IS today's version of the BBC Micro. AFAIK, the BBC Micro was a cheap design to encourage computer education since regular PCs were very expensive. I too cut my teeth on a BBC Micro. My school had ~20 of them. If they'd bought PCs, they would have had maybe 5? The Raspberry Pi will do the same thing today, especially in poor countries which don't have computers as a matter of course in their schools. You're talk…

The BBC Micro was actually quite expensive compared to the other micros of the time. (I don't think the IBM PC was ever considered a "micro", and other micros were probably more capable anyway.) If I remember correctly, the goal was not to produce a design that would compete mostly on cost but rather one that was British and would do the flashy stuff the BBC wanted to show on their computing series. I agree that the…

> I agree that the Raspberry Pi will be revolutionary, not because it will rejuvenate computer science teaching, but simply rather because it's a cheap computer.

Yep. It looks we were mostly in agreement then! :)

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