OpenCL machine..

[NickK]

Ok, my background is simple.

My first MBP 15" was struck down by the nvidia-gate just after the replacement program ended.

My second MBP 15" has the doom Radeon 6750M .. it's GPU is failing with hangs etc.

I want to build an OpenCL crunching machine under linux/OSX. OpenGL performance isn't so much of a problem as this isn't about gaming. The GPU should have a decent processing performance in each - minimum of 2GB ram and 512 pipelines.
The work it's doing is realtime image processing.

I have had direct AMD OpenCL compiler issues - I found a bug in the runtime OpenCL driver that doesn't have a workaround that AMD have verified as an issue but are not committing to a fix for not can they say when Apple would have a fix for. So as this seems to be a reoccurring issue with AMD that others have had.. screw them.

I'll be sticking with OpenCL as it's semi portable at least..

Now that leaves me with two options:
* Apple with Intel Iris Pro (current top MBP has a Radeon - so scratch that model)
* Linux box with nVidia/Intel GPUs


Now portability is a plus point.. but Intel Iris Pros are unknown to me.

Any thoughts?

 

[Orangey]

The Skylake iGPU is supposed to be a decent leap.

http://www.kitguru.net/components/g...s-performance-of-skylake-gpus-by-50-per-cent/
http://hwbot.org/newsflash/2764_sky...nd_gpgpu_performance_figures_at_sisoft_sandra

Perhaps a cheap NV card and a cobbled-together Linux system in the meantime? Or one of those external laptop GPUs?

http://www.pcworld.com/article/2839...you-add-a-desktop-video-card-to-a-laptop.html

 

[D.P.]

I would stick with nvidia TBH, great support and very mature system for this kind of work. Known but unfixed issues are par of the course for AMD it seems, and is largely why nvidia is the de facto standard for GPU compute.

Amd's Linux support is dire, and has been for the last 20 years since I have been using Linux (and likely terrible for many years before that!).

 

[nomadd]

I want to build an OpenCL crunching machine under linux/OSX. OpenGL performance isn't so much of a problem as this isn't about gaming. The GPU should have a decent processing performance in each - minimum of 2GB ram and 512 pipelines.
The work it's doing is realtime image processing.

Now that leaves me with two options:
* Apple with Intel Iris Pro (current top MBP has a Radeon - so scratch that model)
* Linux box with nVidia/Intel GPUs


Now portability is a plus point.. but Intel Iris Pros are unknown to me.

Any thoughts?

Wouldn't touch Apple with an - overpriced - bargepole.

Would want a much more powerful solution than Iris Pro.

GTX 970 would give great bang-for-the-buck: http://www.anandtech.com/show/8568/the-geforce-gtx-970-review-feat-evga/14

 

[meldarthx]

Wait you're upset with AMD because they can't tell you when a fix is coming from Apple on opencl issue.......that makes sense. Remember opencl is pretty much controlled by Apple; so you should also be submitting this issue to them *but getting them to fix issues is always fun*

Have you checked to see if this issue effects Nvidia? Its also known AMD's cards are faster in opencl than Nvidia.....

With that said; AMD runs opencl better but if you're effected by a bug that you don't know when it will be fixed....well guess decide what's in your budget and go with that.

 

[D.P.]

Wait you're upset with AMD because they can't tell you when a fix is coming from Apple on opencl issue.......that makes sense. Remember opencl is pretty much controlled by Apple; so you should also be submitting this issue to them *but getting them to fix issues is always fun*

Have you checked to see if this issue effects Nvidia? Its also known AMD's cards are faster in opencl than Nvidia.....

With that said; AMD runs opencl better but if you're effected by a bug that you don't know when it will be fixed....well guess decide what's in your budget and go with that.

the issue is with the AMD driver surprise surprise

 

[r7slayer]

the issue is with the AMD driver surprise surprise

Why is that a surprise?

 

[meldarthx]

Seriously did you even read what he said; AMD can't fix the issue because the fix has to come from Apple.....FFS.....*sighs*

 

[D.P.]

Why is that a surprise?

I first the internet sarcasm smily!

 

[D.P.]

Seriously did you even read what he said; AMD can't fix the issue because the fix has to come from Apple.....FFS.....*sighs*

That is not what the OP said. The OP stated that the issue is related to the AMD compiler, AMD have verified the issue but have not committed to a release date of a fix.

 

[D.P.]

https://www.change.org/p/advanced-m...mpiler-drivers-and-eventually-opensource-them

In this open letter we urge AMD shareholders, executives, as well as engineers, to increase quality of Graphic Card's open source driver/OpenCL compiler [1] or fully Open-Source closed driver.

The issues that disallow us from choosing Radeon cards are following:
1. The OpenCL compiler runs out of memory even on strong computers (even more on Linux).
2. Other bugs in OpenCL compiler cause random crashes (more common on Linux).
3. OpenCL seem to have technical problems with "spill registers" and "true functions calls" making it hard to write programs for Radeon cards.
4. In addition, fully working and improved OpenCL open-source driver would convince users who want open-source-only software on their servers.
5. Open-source video BIOS would allow bug fixing. There are OpenRadeonBIOS, but it is in very early phase.

It's almost a year since these bugs were reported. We urge you to prioritize your work on above bugs and improve your support for open-source driver/OpenCl compiler.

http://streamcomputing.eu/blog/2013-08-01/amd-fix-bugs-in-opencl-compilerdrivers/

AMD, fix all the bugs in your OpenCL compiler/drivers
AMD has some very nasty bugs in their OpenCL drivers. They have not been solved for years, or reintroduced.

I dabble in GPU compute from time to time and have plenty of friends and colleagues that are fairly hardcore users - they all swear by CUDA and avoid AMD like the plague for this kind of thing. Same thing for OpenGL and Linux, just avoid AMD. They make find window DX drivers but everything else is painful.

OpenCL may seem an ideal open cross platform solution but it's buggy as he'll from all vendors and is not that cross platform anyway. nvidia don't really support it, many of the other platforms have dropped support. You get intel support but their GPUs are poor choices.

I would prefer it if OpenCL was to really take off and I don't like vendor specific tools but really, CUDA is in a league of its own. It is much more mature, more stable, better supported, more libraries , easier to develop.

 

[MagicBoy]

* Apple with Intel Iris Pro (current top MBP has a Radeon - so scratch that model)

???

Current rMBP is nVidia GT750M.

 

[NickK]

Wait you're upset with AMD because they can't tell you when a fix is coming from Apple on opencl issue.......that makes sense. Remember opencl is pretty much controlled by Apple; so you should also be submitting this issue to them *but getting them to fix issues is always fun*

Have you checked to see if this issue effects Nvidia? Its also known AMD's cards are faster in opencl than Nvidia.....

With that said; AMD runs opencl better but if you're effected by a bug that you don't know when it will be fixed....well guess decide what's in your budget and go with that.

The bug, believe it or not, was discovered whilst using the clFFT library (an AMD developed library). On investigating, AMD have stated that it's an OpenCL runtime issue within the driver (AMD again) that Apple use. The additional point is that if AMD fix it, then apple has adopt the fixed version.
What happens is that for random sized textures, the GPU just simply returns from the runtime without error (so can't detect) but all you receive is a blank texture.


Yep - my mistake - nVidia GPU on the topped MBP:
Intel Iris Pro Graphics & NVIDIA GeForce GT 750M with 2GB of GDDR5 memory and automatic graphics switching.


In terms of cross platform, I think I'd probably stick with OpenCL as it allows (although lower performance) some of the ARM embedded devices to run it. It means I can produce a cut down processing pipeline for specific tasks that the embedded system could be used for.

For the larger tasks - it really looks like the nVidia GPU is the only way togo but at the same time it effectlvely removes the main mac users that have Intel or AMD (again using specific texture sizes and cropping to fit as a limp home measure).

I'm thinking that it may be better to make a processing box for the heavy/development use. Pity the MBP has been made an iPad..

quoting apple Up to 90% faster than previous-generation MacBook Pro with Intel HD Graphics 4000

Hmm that's not a good starting point lol .. and after the first two MBP failing for the same reason - I'm rather reluctant to fork out £2000 for one that would replace the one I have now in terms of capabilities..

 

[humbug]

https://www.change.org/p/advanced-m...mpiler-drivers-and-eventually-opensource-them






http://streamcomputing.eu/blog/2013-08-01/amd-fix-bugs-in-opencl-compilerdrivers/




I dabble in GPU compute from time to time and have plenty of friends and colleagues that are fairly hardcore users - they all swear by CUDA and avoid AMD like the plague for this kind of thing. Same thing for OpenGL and Linux, just avoid AMD. They make find window DX drivers but everything else is painful.

OpenCL may seem an ideal open cross platform solution but it's buggy as he'll from all vendors and is not that cross platform anyway. nvidia don't really support it, many of the other platforms have dropped support. You get intel support but their GPUs are poor choices.

I would prefer it if OpenCL was to really take off and I don't like vendor specific tools but really, CUDA is in a league of its own. It is much more mature, more stable, better supported, more libraries , easier to develop.

Did you not see the date on that? it's more than a year old.

AMD have made a huge strides in Open Drivers since then, its one reason Apply have switched from Nvidia to AMD, OpenCL is also gaining traction in applications, Adobe now support OpenCL while phasing CUDA out.

 

[MagicBoy]

The rMBP is very powerful bit of kit. I got one as a replacement for a problem 2011 expecting to be underwhelmed and it's a cracking bit of kit if you ignore the missing ports sacrificed for "thin-ness". The Intel Iris Pro is surprisingly capable and runs the nVidia 750 very close.

 

[NickK]

The rMBP is very powerful bit of kit. I got one as a replacement for a problem 2011 expecting to be underwhelmed and it's a cracking bit of kit if you ignore the missing ports sacrificed for "thin-ness". The Intel Iris Pro is surprisingly capable and runs the nVidia 750 very close.

Hmm interesting.. how did you get a replacement? My system log and I have images of the GPU hangs available to back my statement up.

The annoying thing is that the MBP is a nice small piece of kit which makes it both useful for astronomy and for keeping the Mrs happy. I think the mrs would prefer that than having a linux box lying around but not the price tag (until I get back into employment after being laid off late Nov).

 

[meldarthx]

I'd check to see if that bug hasn't been fixed already....also which card are you using? normal gaming card or a firepro? there have been a lot of fixes; which humbug pointed out one of the reasons Apple did switch from Nvidia to AMD in their graphics as opencl is now gaining a lot of traction.

Nick that clears a bit up on it. its one of the cart before the horse things; but I'd check I've seen a lot of bugs that have been squashed lately.

 

[NickK]

I'd check to see if that bug hasn't been fixed already....also which card are you using? normal gaming card or a firepro? there have been a lot of fixes; which humbug pointed out one of the reasons Apple did switch from Nvidia to AMD in their graphics as opencl is now gaining a lot of traction.

Nick that clears a bit up on it. its one of the cart before the horse things; but I'd check I've seen a lot of bugs that have been squashed lately.

The current GPU is a 6750M. The problem was passed from the AMD front end folkts to the AMD OpenCL team who came up with the diagnosis (after about 3 months!).

My thinking here is that it's good to design the system for Intel Iris *if* that is the current mainstay of people's mac experience for the use of the application. The OpenCL application is used for realtime astronomy observations - this means laptop usage next to the telescope (or inside the tent for warmth!). I also have a process in mind that would be non-realtime but the level of processing would benefit from something heavier duty - which could benefit from the power but could equally be processed on a slower GPU for a longer period.

Only thing is that my current MBP is already doomed :/

 

[CAT-THE-FIFTH]

Sadly the OpenCL performance of consumer Nvidia GPUs is not brilliant - its why both the new iMac and Mac Pro have AMD Tonga and Hawaii based GPUs.

OTH,Intel has made some decent strides forward with their IGPs and do quite well in comparison to equivalent AMD ones.

 

[NickK]

Reading this.. http://www.anandtech.com/show/8568/the-geforce-gtx-970-review-feat-evga/14 it appears that the AMD R9 wipes the floor with the nVidia GPU for OpenCL - probably the GPU core design have a better performance but the nVidia cores can be clocked higher so you get more cycles resulting in a higher single precision performance.

However I'm accutely aware of the benchmark games played by both sides and that these are probably the Windows non-opensource drivers too.

I'd be happy to run with a slower GPU in the laptop but that R9 double precision is probably worth verifying the results for for a box based configuration.