Xeon PHI & Vray?

[vlado]

What Teodor said; we got the OpenCL driver for Xeon Phi, but our tests so far have been with direct compilation of the code for the card and not through OpenCL.

Best regards,
Vlado

[AndresAhumada]

xeon phi run based in x86... this is the best... 1 teraflop for IM?

[naxos]

I should get a Phi board for testing in some days... so i hope it is Windows-ready, and i hope i'll be able to test some render engines onto it...

Any chances to be involved in beta-test program ? I forgot to ask Ivan, Vassil or Konstantin on the last FMX show

Regards.

[vlado]

That's a lot of hopes

We are still some way away from having something to test. Things mostly work, but there is weird stuff going on.

Best regards,
Vlado

[Dariusz Makowski (Dadal)]

That's a lot of hopes

We are still some way away from having something to test. Things mostly work, but there is weird stuff going on.

Best regards,
Vlado

I know how you fell. I got weird stuff going on all the time at work lol.

Happy there is stuff working !

[schultzeworks]

"I just got here question": I thought the PHI cores were pretty straightforward "co-processors," so why do you have to write custom code for them? I was hoping they just added 60 cores and acted as if you had a render farm internally ... and bingo ... that was all you needed. Can you clarify just a little?

[vlado]

Where did I say that we wrote custom code for it?

Best regards,
Vlado

[t.petrov]

schultzeworks:
The Phi has 228 x86 cores, but they are not the same as the cores in a normal CPU.
They are slower, lower frequency, in-order and simpler design cores.
They have their own instructions for SIMD and doesn't support SSE, MMX, AVX, only their instruction set for vector data.

So to get a good performance on the Phi you need massive parallelism in the algorithms. Every serial part of the program is 10-20 times slower than a normal CPU.
We need to do some tweaks and improvement to V-Ray to make it work efficiently on the Phi.

[chuckie7413]

So will these tweaks result in a separate version for vray just for PI architecture or will these tweaks work on a universal build of vray that will maintain the current default cpu performance as well?

Rich

[vlado]

So will these tweaks result in a separate version for vray just for PI architecture or will these tweaks work on a universal build of vray that will maintain the current default cpu performance as well?

No idea at all yet. Of course, we'll try to avoid separate code paths as much as possible; we have enough trouble with the duplicated code on the GPU as it is...

Best regards,
Vlado

[Macker]

Any progress on this? Just curious as I saw they had released embree 1.1 which apparently includes support for the Phi...

http://embree.github.io/

The kernels are optimized for photo-realistic rendering on the latest Intel® processors with support for SSE, AVX, and 16 wide Xeon Phi vector instructions. In version 2.0 Embree now also supports applications written with the Intel SPMD Programm Compiler (ISPC, http://ispc.github.com) which makes it possible to write a renderer in ISPC that leverages SSE, AVX, and Xeon Phi instructions without any code change.

[Macker]

Nay?

I can't help but feel these would be a great alternative to GPU rendering.

[vlado]

I can't help but feel these would be a great alternative to GPU rendering.

That is, unfortunately, an opinion that I can't share right now... Plus I'm not really thrilled at the prospect of rewriting things yet again for another hardware architecture without clear performance benefits.

Best regards,
Vlado

[Dariusz Makowski (Dadal)]

Nay?

I can't help but feel these would be a great alternative to GPU rendering.

I have mixed opinion about it but thing to remember. In order to support xeon PHI card you need xeon CPU and so on as far as I remember. So it may be a very expensive hardware exchange for some people and gpu might just be better money/power ration option.

[t.petrov]

In order to support xeon PHI card you need xeon CPU and so on as far as I remember.

I don't think this is correct. Our machine with the PHI has Xeons in it, but I doubt it will be a problem to put the card in a regular desktop machine.