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Re: OpenACC in GCC - how does it not violate the license?
- From: Jeff Hammond <jeff dot science at gmail dot com>
- To: Jeff Law <law at redhat dot com>
- Cc: Alec Teal <a dot teal at warwick dot ac dot uk>, GCC <gcc at gcc dot gnu dot org>
- Date: Sun, 17 Nov 2013 08:32:35 -0600
- Subject: Re: OpenACC in GCC - how does it not violate the license?
- Authentication-results: sourceware.org; auth=none
- References: <52884CE8 dot 2050002 at warwick dot ac dot uk> <52885287 dot 9030202 at redhat dot com>
> On Nov 16, 2013, at 11:22 PM, Jeff Law <law@redhat.com> wrote:
>
>> On 11/16/13 21:58, Alec Teal wrote:
>> Now while great, is this true!? Nvidia (IIRC, this was like a year ago
>> though) don't even give out the instruction set for their GPUs, can we
>> have GCC targeting closed things? Also there (must be and is) a Cuda
>> runtime, wouldn't we need an open runtime to link against?
> The various projects looking at supporting OpenACC are, to the best of my knowledge, targeting PTX, which is a virtual ISA from NVidia which is published.
>
> Going from PTX to the actual instructions for the particular GPU is the job of a runtime system which would be provided by NVidia.
>
If one wants to tilt at these windmills, we should belabor the lack of open documentation of the microcode corresponding to the x86 instruction set.
Jeff
> However, there's no reason why OpenACC couldn't target the host CPU or another GPU. In fact, that's what I'd initially do if I were working on this.
>
>>
>> This is by no means an accusation, I'm sure he's doing fine work; but
>> he's doing something I didn't think the GPLv3 allowed (so I want to be
>> corrected) he seems to have added something that requires a closed
>> runtime for a target with a closed instruction set - probably for Nvidia
>> (as he is responsible for "strategic partnerships" with them)
> To answer that question you'd need to talk to your lawyer.
>
> jeff