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Fixed three bugs that made Qwen3.5-122B a daily driver on Mac Studio

mrzk.io

11–20 of 36 posts

Re: Fixed three bugs that made Qwen3.5-122B a daily driver on Mac Studio

#12
post #3

The most counter-intuitive bug was that a unique message ID in the system prompt broke the entire KV cache. Since the cache requires byte-exact matches, that changing ID forced a full re-compute on every turn, turning warm contexts into cold fills. I've open-sourced the fork (qMLX) and a benchmark script (bench_qmlx.py) that separates prefill/decode metrics. I chose to fork rather than submit a PR because these hybri…

> a unique message ID in the system prompt broke the entire KV cache. Since the cache requires byte-exact matches, that changing ID forced a full re-compute on every turn, turning warm contexts into cold fills.

This is (part of) the same problem that initially lead Anthropic to ban non-Claude Code clients from using the subsidized subscription: A full to-the-second datetime stamp in the system prompts of OpenCode, and I believe Pi as well, invalidated the caches, making this a very expensive use of their compute very quickly.

They even had Anthropic employees submit PRs (or maybe just open issues, I’d have to check) to these other clients/harnesses because the cache misses were hitting them so hard.

Re: Fixed three bugs that made Qwen3.5-122B a daily driver on Mac Studio

#13
post #9
post #6

I appreciate the amount of detail in the post, I think it's a useful addition to the space. That said, I have to read LLM output all day all the time, and I would implore you to take the time to explore your own voice a bit more. > Two separate things then happened, and it is worth keeping them apart. Is one of those phrases claude spits out nonstop.

Ahhh yeah, I’m not going to sit here and say I don’t use Claude to clean up my writing (ie make it actually coherently laid out). In all honestly I tend to write in a rambling stream of consciousness style across random scrap markdown files (ha), but point is taken.

> In all honestly I tend to write in a rambling stream of consciousness style

At this point that'd be a welcome respite from every single blog post being written in the same exact AI tone.

Re: Fixed three bugs that made Qwen3.5-122B a daily driver on Mac Studio

#14
post #11

Sorry but I'm not reading an AI slop article no matter how pertinent or interesting the subject is. You want my attention? Earn it. Write it yourself.

It's fine, if you don't want to read it you don't have to read it, nobody's forcing you.

Re: Fixed three bugs that made Qwen3.5-122B a daily driver on Mac Studio

#16
post #6

I appreciate the amount of detail in the post, I think it's a useful addition to the space. That said, I have to read LLM output all day all the time, and I would implore you to take the time to explore your own voice a bit more. > Two separate things then happened, and it is worth keeping them apart. Is one of those phrases claude spits out nonstop.

I caught the title "The real work..." labelizing things in a sort of weird phrasing like this is the one I've seen a lot.

Re: Fixed three bugs that made Qwen3.5-122B a daily driver on Mac Studio

#19
post #11

Sorry but I'm not reading an AI slop article no matter how pertinent or interesting the subject is. You want my attention? Earn it. Write it yourself.

I'd rather have a ai-written article then no article at all. I think this is a real struggle. Writing an article takes time that could be spent on improving the product. Would I prefer a human article, yes. But if the alternative is "no article", then that's how it is.

Re: Fixed three bugs that made Qwen3.5-122B a daily driver on Mac Studio

#20
post #9
post #6

I appreciate the amount of detail in the post, I think it's a useful addition to the space. That said, I have to read LLM output all day all the time, and I would implore you to take the time to explore your own voice a bit more. > Two separate things then happened, and it is worth keeping them apart. Is one of those phrases claude spits out nonstop.

Ahhh yeah, I’m not going to sit here and say I don’t use Claude to clean up my writing (ie make it actually coherently laid out). In all honestly I tend to write in a rambling stream of consciousness style across random scrap markdown files (ha), but point is taken.

I was thinking to myself as I was reading the post that here we go again - it's like how much can a man take. It's not that it's unclear... because it is easy to read. I also long for regular old human writing, warts and all.
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