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I think the principle things that have changed since this article was written is mostly each category taking inspiration from the other. For example, SIMD inst

I think the principle things that have changed since this article was written is mostly each category taking inspiration from the other. For example, SIMD instructions gained gather/scatter and even masking of instructions for divergent flow (in avx512 that consumers never get to play with). These can really simplify writing explicit SIMD and make it more GPU-like. Conversely, GPUs gained a much higher emphasis on caching, sustained divergent flow via independent program counters, and subgroup instructions which are essentially explicit SIMD in disguise. SMT on the other hand... seems like it might be on the way out completely. While still quite effective for some workloads, it seems like quite a lot of complexity for only situational improvements in throughput.

yosefk 2y ago
The basic architecture still matters. GPUs still lose throughput upon divergence regardless of their increased ability to run more kinds of divergent flows correctly due to having separate PCs, and SIMD still has more trouble with instruction latency (including due to bank conflict resolution in scatter/gather) than barrel threaded machines, etc. This is not to detract from the importance of the improvements to the base architecture made over time
- Remnant44 2y ago
  agreed! The basic categories remain, just blurring a bit at the edges.
anonymoushn 2y ago
After primarily using AVX2, I don't think masked instructions and scatter/gather are particularly useful. Emulating masked computations with a blend is cheap. Emulating compress and some missing shuffles is expensive. Masked stores and loads don't really help with anything except for an edge case where they don't cause page faults on the part that was masked out.
- petermcneeley 2y ago
  On the gpu a masked out load is a nop. It certainly is better. And scatter functionality is probably quite painful to emulate without the intrinsics.

yosefk 2y ago

The basic architecture still matters. GPUs still lose throughput upon divergence regardless of their increased ability to run more kinds of divergent flows correctly due to having separate PCs, and SIMD still has more trouble with instruction latency (including due to bank conflict resolution in scatter/gather) than barrel threaded machines, etc. This is not to detract from the importance of the improvements to the base architecture made over time

Remnant44 2y ago
agreed! The basic categories remain, just blurring a bit at the edges.

anonymoushn 2y ago

After primarily using AVX2, I don't think masked instructions and scatter/gather are particularly useful. Emulating masked computations with a blend is cheap. Emulating compress and some missing shuffles is expensive. Masked stores and loads don't really help with anything except for an edge case where they don't cause page faults on the part that was masked out.

petermcneeley 2y ago
On the gpu a masked out load is a nop. It certainly is better. And scatter functionality is probably quite painful to emulate without the intrinsics.