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DiffusionGemma: 4x Faster Text Generation

A few days ago I was just thinking that Google never talked about their diffusion text generation model after demoing it at I/O a year ago. The rumor is that it was too expensive to run, but with the provided chart using the same 1x H100 hardware and comparing DiffusionGemma to regular Gemma, that shouldn't be the case. I'm curious what the downside for this speed is here aside from being slightly weaker than Gemma.

an hour agominimaxir

> I'm curious what the downside for this speed is here

"DiffusionGemma's speedup is designed for local and low-concurrency inference. In high-QPS cloud serving, autoregressive models can be deployed to saturate compute efficiently, so DiffusionGemma's parallel decoding offers diminishing returns and can result in higher serving costs"

22 minutes agoac29

I think this is the future. The sort of left-field rumble that turns into a quake in 5 years.

11 minutes agokkukshtel

This may be the future of local models.

The thing is, diffusion models perform somewhat worse than autoregressive on text. So you lose some performance.

Speed is the big advantage. Autoregressive when doing local inference is mostly memory bound; you're doing one token at a time, for each token you need to load all weights. MTP helps a bit by allowing you to draft tokens in a smaller model and then verify them in parallel with the larger model, allowing you to do a few computations for every memory load, but because you're still doing tokens sequentially and need to discard invalid drafted tokens, you can only get so much speedup.

For hosted models, however, you can batch many token generations together, fully utilizing all of the compute while no longer being bottlenecked on memory bandwidth. So they are already operating at close to max efficiency.

So, diffusion kind of loses its beneifit in hosted models. Sure, maybe you could pay more to have slightly lower latency responses by doing diffusion for one user at a time instead of autoregressive for many in parallel. But given that it also reduces accuracy, it's hard to see where you'd really want that. Unless they're able to bring it up to par with autoregressive, it seems like it's a bit of a dead out outside of local models where you're generally just doing one thing at a time.

a few seconds agolambda

We need more local open weight models that are performant and just as good (or good enough) as the best frontier ones.

Then you will be able to achieve Jevons Paradox and enjoy the same “productivity gains” without paying for these extortionate token prices by closed model providers or have it as cheap as possible.

And especially, no silent nerfing of the model.