vello

Yeah, sometimes atomics perform way better than you expect them to. Check out the linkedlist benchmark in my suite, 12.1 G elements/s on AMD 5700 XT using DX12. That's a respectable fraction of raw memory bandwidth. Carrying over intuition from CPU land, you'd expect it to be very slow. Looking at the ISA[2] you can get a glimpse of the magic that happens under the hood to make that happen. (Note: this test case is slightly simplified from what's in the repo for pedagogical reasons). [1]: https://github.com/linebender/piet-gpu/blob/master/tests/sha... [2]: https://shader-playground.timjones.io/da907f46d8bace9e5db7bd...

This is top-notch and very impressive work. I'm currently in the middle of tuning performance of piet-gpu for the Pixel 4[1], and I find myself relying on similar open resources from the Freedreno project. When the time comes to get this running efficiently on M1, having detailed knowledge of the hardware will be similarly invaluable - just the info on registers and occupancy is an important start. Is there a way to support the work? [1]: https://github.com/linebender/piet-gpu/issues/83

The original piet-metal codebase has a tweak where very thin lines are adjusted to thicker lines with a smaller alpha value, which improves quality there. This has not yet been applied to piet-gpu. One of the stated research goals [1] of piet-gpu is to innovate quality beyond what is expected of renderers today, including conflation artifacts, resampling filters, careful adjustment of gamma, and other things. I admit the current codebase is not there yet, but I am excited about the possibilities in the approach, much more so than pushing the rasterization pipeline as you are doing. [1]: https://github.com/linebender/piet-gpu/blob/master/doc/visio...