gladoscc
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Re: Performance

Mon Dec 12, 2011 10:20 am

[quote]Quote from jamesh on December 12, 2011, 10:14
[quote]Quote from gladoscc on December 12, 2011, 09:53
[quote]Quote from ChrisR on December 11, 2011, 20:47
[quote]Quote from jamesh on December 11, 2011, 10:32
The Nokia phone uses a Nokia Arm (?) core + a separate Videocore GPU (2763). The Pi has a single Arm core built in the the same die as the Videocore GPU (2835). However, the Pi Arm core is slower than the Nokia one. (700 vs 1000?? Don\'t know the Nokia core speed)
[/quote]

The Nokia hardware has a customized ARM11 at 1GHz, which is pretty much the same in terms of supported features as the core in the Pi, so is about 30% faster based on clock speed only but there may be a difference in memory performance which would probably impact a GL benchmark. Also, the Nokia system has 128MB of dedicated RAM attached to the GPU which is likely to be faster than the shared memory system used in the Pi. In total, the available headroom for graphics performance should be higher on the Nokia 701/700/603 family.

With that in mind, it\'s (IMO) very unlikely that the Pi will beat the 701 benchmarks, but there are significant architectural differences in both hardware and software which makes predicting Pi performance based on 701 performance rather troublesome.

[/quote]
If that is true, then the graphical power of the pi is really disappointing. [/quote]

Whuh? What do you mean? How can you make that assessment from the comment you quote?

In fact, the GPU in the 701 accesses memory in the same way as the BRCM2835, it\'s just that in the 2835, it has to share the bus with the Arm, so it that is doing a lot (and I mean a lot) of memory accessing for some reason then there may be an impact on the GPU memory access speed, but to be honest it won\'t be that great - you need to be really REALLY hammering it to have an noticable effect.

Haven\'t done the tests yet, but I think the Raspi benchmarks will be pretty much the same or better that the 701.
[/quote]

\"(IMO) very unlikely that the Pi will beat the 701\"

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RaTTuS
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Re: Performance

Mon Dec 12, 2011 11:02 am

It\'s faster than a bbc and that had elite.
it\'s faster than an atari st and that had falcon
it\'s faster than Archimedes and that had lots of stuff.

all all down to how you code ;-p
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Jessie
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Re: Performance

Tue Dec 13, 2011 2:21 am

I\'m not so sure why people get so hung up on the performance. If I can play indie and retro games that will be plenty. When it is time for serious hardcore games I will seat myself in front of my PC. Would it be nice if this $35 PC was a replacement for a mid-grade GeForce or Radeon adapter? Yes, but it won\'t happen.

If enough R-Pis get sold the games will come, and great games arnt forged from cutting edge graphics they are crafted with great storys, top notch gameplay, and artistic style.

jmlxg
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Re: Performance

Tue Dec 13, 2011 4:50 am

The GPU is slightly faster than the SGX543MP2 in the Ipad 2. 24GFLOPS vs about 19 GFLOPS of GPU power but I think the raspberry PI will use more power than the iphones do.

ross
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Re: Performance

Tue Dec 13, 2011 5:03 am

[quote]The GPU is slightly faster than the SGX543MP2 in the Ipad 2 [...] but I think the raspberry PI will use more power [/quote]

Pretty much the opposite of both of those: the GPU in the R-Pi is not as fast as the GPU in the A5 but is lower power.

ChrisR
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Re: Performance

Tue Dec 13, 2011 9:13 pm

[quote]Quote from gladoscc on December 12, 2011, 10:20
[quote]Quote from jamesh on December 12, 2011, 10:14
Whuh? What do you mean? How can you make that assessment from the comment you quote?

In fact, the GPU in the 701 accesses memory in the same way as the BRCM2835, it\'s just that in the 2835, it has to share the bus with the Arm, so it that is doing a lot (and I mean a lot) of memory accessing for some reason then there may be an impact on the GPU memory access speed, but to be honest it won\'t be that great - you need to be really REALLY hammering it to have an noticable effect.

Haven\'t done the tests yet, but I think the Raspi benchmarks will be pretty much the same or better that the 701.
[/quote]

\"(IMO) very unlikely that the Pi will beat the 701\"
[/quote]

I meant more that you would be likely to see very similar results in practise. Benchmarks might be a bit lower, but remember that there is a completely different OS architecture in place for the 701 so it\'s really hard to draw any conclusions ahead of having the Pi in your hand. It\'s always been an academic comparison up until now if Symbian\'s microkernel architecture has much performance impact on high bandwidth applications, and this hardware is sufficiently close that you could probably make a good argument about it with some benchmarking. Previously, there hasn\'t been any public HW that supported both. Also, nobody has really seen what the Nokia hardware in the 701 can do up to now, I\'d put money down that 99% of the games available for it are written for the previous generation GPU so you\'re only seeing a fraction of the power.

Anyway, (again IMO) the 701 and the Pi both have plenty of power for just about anything you\'d want to do. I would be very surprised to see the same kind of AAA games being written for the Pi as you get on the iPhone - who is going to spend the money to develop them? Open source games don\'t normally have the same kind of assets that you get in big titles regardless of any technical merit.

jamesh
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Re: Performance

Tue Dec 13, 2011 9:38 pm

The major problem with the Nokia architecture isn\'t the OS itself but the myriad of software layers and hoops you have to go through to get the data to and from the GPU (whoever makes it), especially video and stills from the camera. It could be better....

Notwithstanding that, the 701 and similar need to communicate to the GPU over an external bus as it on a separate die, with associated communication delays. In the Raspi the Arm and the GPU are on the same die, which means they can have shared memory. Still not a simple task as you need to translate from Arm address space to GPU which takes cycles, but still a bit faster than accessing a coprocessor GPU I believe. The communication differences make direct comparison rather more difficult even though the GPU\'s are the same.

I believe any software for Symbian that uses OpenGL or OpenVG should run accelerated on the latest gen Symbian Nokias, without recompiling, but I could be wrong. Angry Birds certainly runs using the GPU at full tilt.
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reiuyi
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Re: Performance

Wed Dec 14, 2011 1:02 am

Comparing different processor architectures based on speed is pretty bad, you know. Certainly when involving Android, the java-based applications are quite noticeably slower (read: less efficient) than lower-level programming languages you could use on the raspberry pi..

These absolute performance discussions are terrible, regardless. Ten years ago, my browser worked just fine on a 333mhz intel cpu. Nowadays my browser runs slower on my dual core. The efficiency of code, the programming language (level) it\'s in and the amount of optimization that went into it determines the speed of an application.

For $25, you\'re getting quite a lot of computer for your money. The processing speed should be way enough for education, writing, spreadsheet, media, browsing, perhaps even that open-source copycat of SPSS will work!

gladoscc
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Re: Performance

Wed Dec 14, 2011 4:32 am

[quote]Quote from reiuyi on December 14, 2011, 01:02
Comparing different processor architectures based on speed is pretty bad, you know. Certainly when involving Android, the java-based applications are quite noticeably slower (read: less efficient) than lower-level programming languages you could use on the raspberry pi..

These absolute performance discussions are terrible, regardless. Ten years ago, my browser worked just fine on a 333mhz intel cpu. Nowadays my browser runs slower on my dual core. The efficiency of code, the programming language (level) it\'s in and the amount of optimization that went into it determines the speed of an application.

For $25, you\'re getting quite a lot of computer for your money. The processing speed should be way enough for education, writing, spreadsheet, media, browsing, perhaps even that open-source copycat of SPSS will work![/quote]

I disagree on them being \'terrible.\' A i7 will be faster than a i5 (same gen). It doesn\'t matter how much a code is optimized - i7 will run faster compared to i5.

Also, please don\'t think of me as complaining. I\'m just interested in the performance of this, I am not buying it to replace my gaming PC.

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Emanuele
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Re: Performance

Wed Dec 14, 2011 6:29 am

[quote]Quote from ChrisR on December 13, 2011, 21:13
Anyway, (again IMO) the 701 and the Pi both have plenty of power for just about anything you\'d want to do. I would be very surprised to see the same kind of AAA games being written for the Pi as you get on the iPhone - who is going to spend the money to develop them? Open source games don\'t normally have the same kind of assets that you get in big titles regardless of any technical merit.
[/quote]

I sort of second that. The issue is the lack of ways to make money out of games.

I\'d focus on porting existing opensource games and writing new opensource games. Let\'s take vdrift (http://vdrift.net) as an example. I\'m of course speculating. I do believe that a naive port (i.e. essentially a simple OpenGL to OpenGL ES conversion) would be pretty much unplayable. Why? Because: 1) The physics engine is quite realistic and the ARM side of the raspi is weak. 2) The graphics pipeline is tuned for a different architecture; the API might be similar (OpenGL vs OpenGL ES), but one thing is to design for a graphics card with very fast on-board graphics memory and another thing is to design for a graphics core with very fast on-die cache.

Does it mean that the raspi cannot have a great racing simulator? While I would be cautious in making comparisons with the XBox and PS2 (the graphics cores might be comparable, but the memory subsystems aren\'t), I cannot see why raspi couldn\'t have something like Forza 1 / GT3 running smoothly. The real question is: is anyone going to take vdrift, rewrite a simpler physics engine, rewrite parts of the graphics pipeline and scale the art assets (e.g. reduce the polygon count of some models)?

Asgo
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Re: Performance

Wed Dec 14, 2011 7:51 am

I for one would bet, that in the end the IO performance will be the limiting factor.
At least when dealing with some real world applications, which don\'t run entirely from RAM and have to load/write stuff in some regular intervals.

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