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Comment by arcanus | Hacker News Reader

SYCL is a terrible option. The performance of any application on SYCL is currently quite poor. Why drop ROCm (used on the world's largest supercomputer?) for an even more unproven product that AMD has no control over the roadmap?

> Banding together with Intel to support SYCL would in my opinion

Except that Intel has more control over SYCL and has repeatedly hurt AMD products with anticompetitive behavior in the past. Why would AMD permit their software to be controlled be a competitor?

AMD is executing with ROCm NOW, with multiple Top500 supercomputer wins and deployment in major cloud vendors with MI300X. Yes, the software needs to improve, but the practice of throwing out software to start over is not a good strategy.

AMD has far more momentum in the data center than INTC at present.

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I agree about ROCm.

When it comes to comparison to SYCL, HIP is much closer to the spirit of SYCL than ROCm is. Both aim to help writing a single codebase that'll run across multiple hardwares. For now though, the trajectory of SYCL appears much more promising to me than HIP. HIP is already split in two parts for CPU and GPU, which is baffling, and neither part seems to receive much love from AMD.

> The performance of any application on SYCL is currently quite poor.

SYCL can get pretty much equivalent performance in Kernels to eg. CUDA. Try looking at SYCL performance papers on Arxiv. Eg. see [1].

That isn't to say that SYCL code is optimised on every platform without tweaking - you do still need to put effort into target specific optimizations to get the best performance, like you would in the CUDA or HIP.

> Why drop ROCm (used on the world's largest supercomputer?)

Some of the world's largest super-computers / HPC applications do use SYCL for AMD! The application I'm most aware of for this is GROMACS. As to why? - because having 3 version of the same code using different programming APIs is a big maintenance burden.

[1] https://arxiv.org/pdf/2309.09609.pdf

> Some of the world's largest super-computers / HPC applications do use SYCL for AMD! The application I'm most aware of for this is GROMACS. As to why? - because having 3 version of the same code using different programming APIs is a big maintenance burden.

The fact that GROMACS is unwilling to drop CUDA support to stand fully behind SYCL is very telling.

I wouldn't expect them to drop CUDA support, even if SYCL is a viable alternative: * The CUDA backend is mature, featureful, and significant effort has been invested into optimising it on Nvidia hardware. One does not simply throw away a performant, well validated HPC code! * Nvidia GPUs dominate the GPGPU market - unlike AMD's. * The SYCL backend is still is very new in comparison (they even state in the docs to pay extra attention to validation), and doesn't have Nvidia-specific optimisations yet. Why prioritise reimplementing what already exists?

It hardly matters if most desktops and laptops will be running CUDA/SYCL instead.

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