Originally posted by oiaohm
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Originally posted by oiaohm
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Originally posted by oiaohm
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...which reminds me of the greatest evidence that NVidia GPUs are really SIMD machines, at the SM-level: Tensor ops. To utilize the tensor "cores" on Volta, it broke Nvidia's fiction about warps being a batch of threads. They need the entire width of the 32-lane SIMD registers to feed the tensor cores and receive the results.
Warp-based SIMD consists of multiple scalar threads executing in a SIMD manner (i.e., same instruction executed by all threads)
- Does not have to be lock step
- Each thread can be treated individually (i.e., placed in a different warp) -> programming model not SIMD
- SW does not need to know vector length
- Enables memory and branch latency tolerance
- ISA is scalar -> vector instructions formed dynamically
- Essentially, it is SPMD programming model implemented on SIMD hardware
As for the part about vector instructions being formed dynamically, we don't know whether the author is talking about PTX or what. We don't even know which generation of hardware this refers to, or if it's simply wrong about that part. It's one slide in overview material for an intro class on computer architecture. It would be foolish to read into that.
This is a secondary source, at best, and it doesn't even have any citations. Basically, a waste of time. Show me something from Nvidia, or at least more peer-reviewed research papers.
Originally posted by oiaohm
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AMD is quite clear about how their GPUs work. It's straight SIMD, at the CU level.
Originally posted by oiaohm
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Originally posted by oiaohm
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I know you're just searching for "GPU MIMD", though. You're not actually looking at what AMD and Nvidia have published about their GPUs, or what independent researchers have discovered about Nvidia's. When you don't take an unbiased look at the information, but instead look for anything which supports your preconceived notion, that's called "confirmation bias". It's one of the underlying phenomenons that lead people to believe insane conspiracy theories.
Originally posted by oiaohm
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