## ATI released OpenCL SDK with hardware support

Discussions related to GPU Acceleration in LuxRender

Moderators: Dade, jromang, tomb, coordinators

### Re: ATI released OpenCL SDK with hardware support

SATtva wrote:
Dade wrote:Can I say that CPUs are starting to look a bit pathetic ? My poor Q6600 is totally owned by the 4870 The GPU is 9.83 times faster than the CPU

I know now how my next budget on the renderfarm upgrade will be spent. ^_______________^

Ssssshhh, don't tell my credit card, I ordered the components for a new PC yesterday ... I'm going to put so many GPUs inside that poor box

Dade

Posts: 8404
Joined: Sat Apr 19, 2008 6:04 pm
Location: Italy

### Re: ATI released OpenCL SDK with hardware support

Dade wrote:Can I say that CPUs are starting to look a bit pathetic ? My poor Q6600 is totally owned by the 4870 The GPU is 9.83 times faster than the CPU

FINALLY after 25 pages of technobabble a post I can understand! Although I am suffering from a bit of nonbelief, and I need someone to check my math.

Dade's Q6600 should be roughly 2x the processing speed of my E6600. And his 4870 is almost 10x faster than his Q6600. So this means that a 4870 would be ~20x faster than my E6600?

Furthermore, from earlier in this thread:

Dade wrote:Today, I have seen a screenshot of SmallptGPU running on a ATI 5870, it is about 3-4 times faster than my 4870 ... what the hell

Does this mean that if I were to put a 5870 in my little E6600 box that it would render at 60 - 80x what my CPU can do?

This can't be right... Where is my mistake? These numbers are too huge.

Mike
Lux: 0.6.1
Blender: 2.49b
WinXP(32) - E6600 - 4GB
MikeJ

Posts: 221
Joined: Sun Nov 22, 2009 11:37 am

### Re: ATI released OpenCL SDK with hardware support

Mike, don't forget that 5870 has 1600 stream processors on board vs 2-4 cores of mainstream CPUs. ;) They are not as versatile and fast as general-purpose CPU, but massively parallelizeable.
Linux builds packager

SATtva

Posts: 7164
Joined: Tue Apr 07, 2009 12:19 pm
Location: from Siberia with love

### Re: ATI released OpenCL SDK with hardware support

yeah amazing speed..
I used to mess about with early Indigo on a single thread 2.66ghz Pentium and wait for 14-15 hours and I guess if I used two 5870 now the same render would be done in about a minute

refugee

Posts: 11
Joined: Sun Apr 27, 2008 3:20 am

### Re: ATI released OpenCL SDK with hardware support

I just run the caustic.scn on a mac mini with nvidia 9400
Code: Select all
Usage: ./smallptgpu <use CPU/GPU device (0=CPU or 1=GPU)> <workgroup size (0=default value or anything > 0 and power of 2)> <kernel file name> <window width> <window height> <scene file>Reading scene: scenes/caustic.scnScene size: 3OpenCL Platform 0: AppleOpenCL Device 0: Type = TYPE_GPUOpenCL Device 0: Name = GeForce 9400OpenCL Device 0: Compute units = 2OpenCL Device 0: Max. work group size = 512OpenCL Device 1: Type = TYPE_CPUOpenCL Device 1: Name = Intel(R) Core(TM)2 Duo CPU     P8700  @ 2.53GHzOpenCL Device 1: Compute units = 2OpenCL Device 1: Max. work group size = 1[SELECTED] OpenCL Device 0: Type = TYPE_CPU[SELECTED] OpenCL Device 0: Name = Intel(R) Core(TM)2 Duo CPU     P8700  @ 2.53GHz[SELECTED] OpenCL Device 0: Compute units = 2[SELECTED] OpenCL Device 0: Max. work group size = 1Reading file 'preprocessed_rendering_kernel.cl' (size 16931 bytes)OpenCL Device 0: kernel work group size = 1

It sits around 6000K samples a sec. for CPU

Code: Select all
Usage: ./smallptGPU <use CPU/GPU device (0=CPU or 1=GPU)> <workgroup size (0=default value or anything > 0 and power of 2)> <kernel file name> <window width> <window height> <scene file>Reading scene: scenes/caustic.scnScene size: 3OpenCL Platform 0: AppleOpenCL Device 0: Type = TYPE_GPUOpenCL Device 0: Name = GeForce 9400OpenCL Device 0: Compute units = 2OpenCL Device 0: Max. work group size = 512OpenCL Device 1: Type = TYPE_CPUOpenCL Device 1: Name = Intel(R) Core(TM)2 Duo CPU     P8700  @ 2.53GHzOpenCL Device 1: Compute units = 2OpenCL Device 1: Max. work group size = 1[SELECTED] OpenCL Device 0: Type = TYPE_GPU[SELECTED] OpenCL Device 0: Name = GeForce 9400[SELECTED] OpenCL Device 0: Compute units = 2[SELECTED] OpenCL Device 0: Max. work group size = 512Reading file 'preprocessed_rendering_kernel.cl' (size 16931 bytes)OpenCL Device 0: kernel work group size = 192OpenCL Device 0: forced kernel work group size = 32

and around 4500K for GPU
Plus the system noticeable slows down in gpu mode

EDIT
With cornel scene in GPU mode 450K and around 600k in CPU mode... quite a drop off in performance

2nd EDIT
Jens just pointed something out to me: workgroup size set to max changes the GPU results in cornel scene quite dramatically ( for a nv 9400 that is )
GPU mode 840K , CPU mode stayed pretty much the same...

Sheltem

Great work guys!!
Last edited by Sheltem on Sat Jan 09, 2010 2:04 am, edited 1 time in total.
Sheltem

Posts: 122
Joined: Sun Jun 15, 2008 11:06 am

### Re: ATI released OpenCL SDK with hardware support

MikeJ wrote:Dade's Q6600 should be roughly 2x the processing speed of my E6600. And his 4870 is almost 10x faster than his Q6600. So this means that a 4870 would be ~20x faster than my E6600?

SmallptGPU would be 20x faster, MandelGPU would be 124x faster and Luxrender ? No one really know yet.

First of all we have to modify Luxrender to be able to use GPUs. It is not going to be a trivial or short task even if we have now a good idea of how to modify Lux (and the idea is supported by some field experiment).

Do you want me to make an hypothesis of how fast will be the very first rendering done by Lux with the help of a GPU ? I would place my bet on 1.5 - 2 times faster (but it is really hard to say and should become a lot of faster with more time spent on optimizing the software).

MikeJ wrote:Does this mean that if I were to put a 5870 in my little E6600 box that it would render at 60 - 80x what my CPU can do?

This can't be right... Where is my mistake? These numbers are too huge.

The 5870 is probably more than 500-600 times faster than your E6600 on raw floating point computation but it is not like we can just recompile Lux and run on the GPU; the problem is more complex.

An E6600+HD5870 combo would be anyway too unbalanced. The CPU would be too slow to keep the GPU busy. However, in the future, you could buy a 5770 and cut your rendering times in half or 1/3 (by buying a 120euro GPU). This is exactly why we are all excited about this GPU thing: it is high floating point performances at low cost for everyone.

@Sheltem: your result isn't really surprising: your card has 16 streaming processor Vs the 1600 of a HD5870 or the 800 of my HD4870. You can expect a good speed only with the high end of the old generation GPU or the medium/high-end of the new one.

Anyway the point isn't really CPU Vs GPU but CPU Vs CPU+GPU so you will get a speed up on rendering times even if your GPU is slow.

P.S. I uploaded the SmallptGPU 1.6 to http://davibu.interfree.it/opencl/small ... ptGPU.html
It should include all the fix for the Mac and a new optional kernel that can do direct lighting integrator like rendering:

It is quite funny to use, indeed it is really fast.

Dade

Posts: 8404
Joined: Sat Apr 19, 2008 6:04 pm
Location: Italy

### Re: ATI released OpenCL SDK with hardware support

Dade wrote:An E6600+HD5870 combo would be anyway too unbalanced. The CPU would be too slow to keep the GPU busy. However, in the future, you could buy a 5770 and cut your rendering times in half or 1/3 (by buying a 120euro GPU). This is exactly why we are all excited about this GPU thing: it is high floating point performances at low cost for everyone.

Thanks for the thoughtful reply. I had not even considered the CPU/GPU balance issue. I guess it will take some experimentation to know what the minimum CPU requirement will be for each GPU type. Looks like it will be considerable time before the GPU tab will appear in Lux anyway, so I will fade back into the shadows on this topic and let you guys continue to have your fun.

Mike
Lux: 0.6.1
Blender: 2.49b
WinXP(32) - E6600 - 4GB
MikeJ

Posts: 221
Joined: Sun Nov 22, 2009 11:37 am

### Re: ATI released OpenCL SDK with hardware support

@ Dade just out of curiosity: is the cornel scene available as a blender / lux file? I would like to find out how many samples a sec the 'standard' lux is achieving...
I know that isn't exact science and will not be an indication on how much quicker a 'gpuLux' finally might be but hey I'm curios

Sheltem
Sheltem

Posts: 122
Joined: Sun Jun 15, 2008 11:06 am

### Re: ATI released OpenCL SDK with hardware support

@ Sheltem: iám pretty sure , you measured with simple.scn

Jens

jensverwiebe

Posts: 3429
Joined: Wed Apr 02, 2008 4:34 pm

### Re: ATI released OpenCL SDK with hardware support

Sheltem wrote:@ Dade just out of curiosity: is the cornel scene available as a blender / lux file? I would like to find out how many samples a sec the 'standard' lux is achieving...
I know that isn't exact science and will not be an indication on how much quicker a 'gpuLux' finally might be but hey I'm curios

It wouldn't be a fair comparison, the samples produced by Luxrender have far less noise so you can not do a Samples/Sec Vs Samples/Sec comparison ... who care of being fair let's do a test.

Luxrender rendering after 60 seconds (Metropolis+Path):

SmallptGPU after 60 seconds:

Is "Brute Force" going to win over "Being Smart" ? This is not the right question: "Brute Force" and "Being Smart" is going to win over "Brute Force" or "Being Smart".

The number you see above (103K samples/sec Vs 6500K samples/sec), should give you a good idea why I can not keep my hand out OpenCL

P.S. the Lux scene is attached to this message.
Attachments
cornell.lxs
(4.06 KiB) Downloaded 55 times

Dade

Posts: 8404
Joined: Sat Apr 19, 2008 6:04 pm
Location: Italy

PreviousNext

Return to GPU Acceleration

### Who is online

Users browsing this forum: Bing [Bot] and 2 guests