[Libre-soc-dev] svp64 review and "FlexiVec" alternative

[Jacob Bachmeyer]

Jacob Lifshay wrote:
> On Tue, Jul 26, 2022, 17:33 Jacob Lifshay <programmerjake at gmail.com 
> <mailto:programmerjake at gmail.com>> wrote:
>
>     i think we should specifically have the same ISA for cpu and gpu
>     stuff, it makes possible optimizing 3D graphics much more if it
>     becomes wide-spread, as opposed to current GPUs where the vendors
>     basically forbid you from using their native ISA and insist you
>     must use their compiler to process all your gpu code first. Using
>     the same ISA also reduces communication overhead because you can
>     just treat it as a normal multithreaded program, rather than this
>     thing that you have to go to great effort to queue up work for and
>     use special kernel drivers, etc.
>
>
> also, who wouldn't want to use their gpu to run normal cpu tasks too, 
> if it was available? compiling llvm on your 32-core gpu and 16-core cpu!

The programming models are fundamentally different, such that the GPU is 
not going to have the expected performance in other workloads.  To use 
your example, I would expect most GPUs to fare poorly running a 
compiler, such that I would be unsurprised if *one* of those 16 CPU 
cores outperforms the entire GPU on that task.


-- Jacob