Ryan Flaherty

You need to add accumulation and temporal reprojection. For CPUs optimizing the scene for cache hits also matters a lot. Naively using if statements or switch will cause massive slowdowns compared to using goto statements. On a simple scene this should get something that's noisy but shockingly clear. If you notice it looks a bit muddy and blurry with DLSS. So its not actually solving the issue. The image attached is a path tracer with temporal reprojection and running on WebGPU. There's a bit more noise while moving, but its smooth and very usable and instantly converged when you stop. And this is running on old intel iris xe at 1440p. The noise problem oddly gets worse if you decrease resolution. So a light denoiser is honestly the best solution. Imagine how good this would run with a lightweight denoiser. Like you gotta understand. I wasn't even trying. I just had gemini 3 Pro make this in an evening. If I had used vulkan, written it myself it would be even faster. And I bet I could do a lot more optimizations. or heck get a better GPU.

Most programmers are taught that L1 is the “top level” cache on x86. It’s not quite true anymore! Intel calls it the Decoded Stream Buffer (DSB), AMD the OpCache. Only enough room for ~4,000 micro-ops, but there are interesting ways to take advantage of it.

Completely untrue. It is the opposite, everything is actually async but your cpu and the kernel tries really hard to sell you a synchronous model.

Hot Take: Nothing in computing is truly asynchronous at the hardware and instruction level. Everything is synchronous, until a runtime fakes it. People talk about async like it's a magical property of the universe. But at the lowest level, every system is ultimately synchronous. -CPUs appear to execute instructions in order (even though they reorder internally) -Syscalls block unless the OS schedules around them -Hardware is event-driven but still bound by clocks -“Async” functions don’t run in parallel, the runtime schedules them So what’s actually happening? Async is an illusion built by runtimes: -JavaScript: event loop + callback/microtask queue -Rust: executor + waker + poll-based futures -Python: event loop + coroutines -Go: scheduler multiplexing goroutines over OS threads -OS kernels: interrupts + preemptive scheduling Under the hood, it’s all synchronous execution broken into chunks and interleaved by a scheduler. -Async ≠ “parallel” -Async ≠ “multithreaded” -Async = “scheduled synchronous steps that look concurrent” The runtime just decides when your synchronous fragments run. In summary: Every system is synchronous at its core. Async is a runtime abstraction that slices sync operations into interleaved steps that feel concurrent. It's the core concept of Asynchronous. I am always open to feedbacks, because through your feedback I get to know a lot.