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Earlier quoted context omitted.
It appears to be a real term? https://docs.vulkan.org/tutorial/latest/Synchronization/Asyn... Very odd, but perhaps more familiar to graphics programmers? I will say I'd probably call it a stall, which is exactly what the Vulkan docs call it moments later, so :shrug:
"bubble" used to be used a lot more when talking about very deep pipelines, eg Pentium 4 depth.
In general, for some reason CODEX loves CUDA-streams, it's the first optimization it goes for every time when writing GPU kernels. However in many cases this is not a bottleneck, it happens to be so here because the model in the blog is small (2.4ms FW-pass is tiny, and 9B params sit on a single GPU). Large models are closer to 30-40ms. The CPU-GPU sync is 1-2ms, when working on larger MoE models the scheduling of tokens in this way is much less important than for example scheduling of computation/communication or kernel optimization.
I wish the blog would state this at the start with the premise of what has been done, or show that this is indeed the bottleneck with some benchmarking. Otherwise is kind of overselling things imo.
The GPU would be the propeller, the influx is the work, and the operational parameters is what this article's about.
As someone who works in the field, the blog is nice but it has a lot of CODEX fingerprints on it, and it's also very specific to the size of the model in question in a way that is not explicit from the blog until the very last section. In general, for some reason CODEX loves CUDA-streams, it's the first optimization it goes for every time when writing GPU kernels. However in many cases this is not a bottleneck, it ha…
If you scroll down to the section titled "A cost model for the bubble", you will find both benchmark results and us saying, "you get back anywhere from a few percent to a third; more the faster your accelerator/model is".
That's a terrible name for that and I can't say that Hanlon's razor applies. Bubble that everyone's knowingly referring to is the stock market collapsing like in 2001. To choose a headline that can be mistaken for that just to get clicks is shit. You could've called it GPU-CPU pipeline stall, but no, you intentionally chose a name that would be confused for something else just to get clicks?
Regarding the critique on the title: perhaps an analogy can be made to propeller cavitation on ships. Water influx rate, propeller design and operational parameters all influence the detrimental effect of water bubbles forming — deteriorating the system's efficiency. The GPU would be the propeller, the influx is the work, and the operational parameters is what this article's about.
I really appreciate this type of articles. I feel like a lot of knowledge in LLM training and inference is locked inside the heads of practitioners. Similar to compiler engineers before. To work in LLM training/inference you’re expected to know this stuff but to know this stuff you need to be working in the space.
I really appreciate this type of articles. I feel like a lot of knowledge in LLM training and inference is locked inside the heads of practitioners. Similar to compiler engineers before. To work in LLM training/inference you’re expected to know this stuff but to know this stuff you need to be working in the space.
Gentle reminder that while most money is spent on LLM inference, the vast majority of useful AI use is in fact not LLMs. Also, more and more work is poured into making small models. One thing I like about the whole export controls saga is that people are finding creative ways to squeeze performance out of these devices as witnessed in this post. But, if you then look at solutions like vLLM, vLLM will just fill whatev…
Can you explain what you mean here? Are you talking about small neural networks doing specific tasks?
That's a terrible name for that and I can't say that Hanlon's razor applies. Bubble that everyone's knowingly referring to is the stock market collapsing like in 2001. To choose a headline that can be mistaken for that just to get clicks is shit. You could've called it GPU-CPU pipeline stall, but no, you intentionally chose a name that would be confused for something else just to get clicks?