[slurm-users] CUDA vs OpenCL

[Williams, Gareth (IM&T, Black Mountain)]

ROCR_VISIBLE_DEVICES Is the closer analogy. GPU_DEVICE_ORDINAL is in principle more generic (though does have GPU in the name). OpenCL could in principle (can!) run on other devices which could/can have more exotic topology, but for the sake of simplicity are likely to be presented as a list of devices...

Gareth   

-----Original Message-----
From: slurm-users <slurm-users-bounces at lists.schedmd.com> On Behalf Of Valerio Bellizzomi
Sent: Thursday, 6 May 2021 6:35 PM
To: slurm-users at lists.schedmd.com
Subject: Re: [slurm-users] CUDA vs OpenCL

On Thu, 2021-05-06 at 08:00 +0000, Williams, Gareth (IM&T, Black
Mountain) wrote:
> The post has me thinking so I did a little searching... AMD have an 
> offering that supports OpenCL and they are not NVIDIA. They use a 
> different approach:
> https://rocmdocs.amd.com/en/latest/Programming_Guides/Opencl-programmi
> ng-guide.html#masking-visible-devices


Thank you for the pointer. It seems to me that they just name the variable differently (GPU_DEVICE_ORDINAL) but the approach is the same.


> FWIW I did not yet see anything there about cgroups and enforced 
> device visibility/constraints vs playing nicely with environment 
> variables.


Here documentation on device cgroups:
https://rocmdocs.amd.com/en/latest/ROCm_System_Managment/ROCm-System-Managment.html?highlight=device%20cgroups#device-cgroup


> For reference, I have no AMD affiliation and little to no direct 
> experience.
> 
> It is pretty easy to also find what else supports OpenCL (Wikipedia?). 
> What environment to honor seems to me to mostly be a software choice 
> and most of the software is from vendors, albeit sometimes being open 
> source or using on or relying on open source components or layers.
> 
> Gareth
> 
> -----Original Message-----
> From: slurm-users <slurm-users-bounces at lists.schedmd.com> On Behalf Of 
> Valerio Bellizzomi
> Sent: Thursday, 6 May 2021 5:21 PM
> To: slurm-users at lists.schedmd.com
> Subject: Re: [slurm-users] CUDA vs OpenCL
> 
> On Wed, 2021-04-28 at 10:56 +0200, Valerio Bellizzomi wrote:
> > Greetings,
> > I see here https://slurm.schedmd.com/gres.html#GPU_Management that 
> > CUDA_VISIBLE_DEVICES is available for NVIDIA GPUs, what about OpenCL 
> > GPUs?
> > 
> > Is there an OPENCL_VISIBLE_DEVICES ?
> > 
> > 
> 
> Lack of followup lets me conclude that there isn't an OpenCL 
> equivalent of CUDA_VISIBLE_DEVICES. It is unfortunate that this open 
> source software is committed to a single gpu supplier.
>