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nomi_uw

92 karma · joined November 5, 2026

inqiuries: nabilomi@cs.uw.edu
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nomi_uw··on A primer on GPUs and kernel optimization
I don't think it's not a problem, and I'm sure it pops up extremely often in the case of competitions when things are won by margins of +0.01x and hundreds of people are chipping at it with agents for days. This is a very different scenario to what I assume most people might be doing, though.

Thanks for bringing up these points, it's definitely good food for thought to add to the blog!

nomi_uw··on A primer on GPUs and kernel optimization
Seems like the kernel portion of that competition is closed. I can probably compare whatever the serving winner is against JamInfer when it's out (seems like they start that track on the 12th). Main issue being any submission code goes straight to SGLang which I don't think my advisor or university will appreciate spending resources on.

The top of the article shows the e2e times on some math RL tasks, with fp8 weights/activations/KV, comparing against SGLang on two models. They use the same concurrent batch size, quantization scheme, and the final lengths were about the same. I think Qwen3 models are probably very mature compared to Muse by now.

30B-A3B MoE

Jam - 67,241

SGLang - 44,696

+50.4%

8B Dense

Jam - 58,821

SGLang - 41,759

+40.9%

Math RL is pure decode, so kernels are the most major factor here.

Also-- I feel as if this has gone a bit off-track. The point of my reply was to comment on agents being actually decent at benchmark development and usage if you tell them to be, not as a comment on how great the harness is (I even state in the article: "it's a fairly simple and minimal setup that seems to work well.").

I don't think it's a footgun at all, and generally feel like (at least OpenAI's models) tend to do well in stating when there is some caveat to watch out for (they'll probably say when they're about to hack for the user to catch). The benchmarking suite they've made is actually very similar to what's in the open kernel challenge. Given that this was initially made many months ago, I'd think Opus and GPT did a pretty good job if someone is betting $100k+ (in prize money) on a similar suite being decent.

nomi_uw··on A primer on GPUs and kernel optimization
Yes, they can reward hack. However, making sure the model knows what your requirements are (e.g., "do not quantize, meet this set of specifications") can mitigate that, and simply looking at the code briefly (or having the LLM describe it back to you) can mitigate it quite easily. Often, such issues are a result of insufficient specificity by the user. If you tell it just to make the model faster, it'll do it and not assume additional requirements.

Same thing applies to benchmarking, a few guardrails goes a long way. As long as you aren't completely vague ("set up benchmarks", vs. "write tests over a variety of common shapes, be careful to control for environmental variables") the models do quite well. I've checked over the code it's written and it's all fairly reasonable. I do mention cache eviction in the article, this generally wasn't an issue and the model did this automatically on the first pass (back in Opus 4.6 days). I think you might not be giving them enough credit here.

I'm not completely familiar with the writers of this article, but I've never had an LLM try to hack this, even sometimes telling me a target was impossible without quantization or approximation:

"Code based analysis already tells a detailed story, but there is an overlooked parameter: "boundaries of the hardware". " - the myainotez post

This project has spanned several models since Opus 4.5. I think even then such details were trivially known by them, thought they required much more handholding than they do now. I'm honestly not sure how the article writers ran into the hacks they did.

edit: I should mention this article is based on my experience developing an RL and inference framework dealing with trainer-inference mismatch. I don't know if hill-climbing a kernel in an isolated set of benchmarks would perform differently. At the end of the article, I mention what my hill-climber looks like: https://www.nabo.dev/blogs/kernel-primer#section-in-the-age-... It has to go through numerics and correctness checks, then isolated tests for common shapes (where launch parameters are determined by an autotuner, not the agent), followed by end-to-end throughput tests.

nomi_uw··on A primer on GPUs and kernel optimization
Hmm, this is a good point. I tried to be fairly brief on this part and separated a lot of the profiling to a separate page since I usually use AI for benchmarking these days. I do think there are a lot of principles that humans should learn in practice, even if most of this is done with LLMs.

I'll update the post in the coming week with a section on benchmarking. The current post does have some details on measurement, but I agree that maybe it's not covered in the required depth.

nomi_uw··on A primer on GPUs and kernel optimization
Will update, thanks for pointing out.
nomi_uw··on A primer on GPUs and kernel optimization
I appreciate the compliment, yes this is spot on
nomi_uw··on A primer on GPUs and kernel optimization
The post is actually mostly human written! I personally am not a fan of Claude's writing and don't even use Claude (my main subscription is Codex).