We’re excited to announce that Mosaic AI Model Training now helps the total context size of 131K tokens when fine-tuning the Meta Llama 3.1 mannequin household. With this new functionality, Databricks prospects can construct even higher-quality Retrieval Augmented Era (RAG) or device use methods by utilizing lengthy context size enterprise information to create specialised fashions.
The dimensions of an LLM’s enter immediate is set by its context size. Our prospects are sometimes restricted by quick context lengths, particularly in use instances like RAG and multi-document evaluation. Meta Llama 3.1 fashions have an extended context size of 131K tokens. For comparability, The Nice Gatsby is ~72K tokens. Llama 3.1 fashions allow reasoning over an in depth corpus of knowledge, decreasing the necessity for chunking and re-ranking in RAG or enabling extra device descriptions for brokers.
Wonderful-tuning permits prospects to make use of their very own enterprise information to specialize present fashions. Latest methods similar to Retrieval Augmented Fine-tuning (RAFT) mix fine-tuning with RAG to show the mannequin to disregard irrelevant data within the context, enhancing output high quality. For device use, fine-tuning can specialize fashions to raised use novel instruments and APIs which can be particular to their enterprise methods. In each instances, fine-tuning at lengthy context lengths permits fashions to purpose over a considerable amount of enter data.
The Databricks Information Intelligence Platform permits our prospects to securely construct high-quality AI methods utilizing their very own information. To verify our prospects can leverage state-of-the-art Generative AI fashions, you will need to assist options like effectively fine-tuning Llama 3.1 on lengthy context lengths. On this weblog put up, we elaborate on a few of our current optimizations that make Mosaic AI Mannequin Coaching a best-in-class service for securely constructing and fine-tuning GenAI fashions on enterprise information.
Lengthy Context Size Wonderful-tuning
Lengthy sequence size coaching poses a problem primarily due to its elevated reminiscence necessities. Throughout LLM coaching, GPUs have to retailer intermediate outcomes (i.e., activations) with the intention to calculate gradients for the optimization course of. Because the sequence size of coaching examples will increase, so does the reminiscence required to retailer these activations, probably exceeding GPU reminiscence limits.
We remedy this by using sequence parallelism, the place we break up a single sequence throughout a number of GPUs. This strategy distributes the activation reminiscence for a sequence throughout a number of GPUs, decreasing the GPU reminiscence footprint for fine-tuning jobs and enhancing coaching effectivity. Within the instance proven in Determine 1, two GPUs every course of half of the identical sequence. We use our open supply StreamingDataset’s replication feature to share samples throughout teams of GPUs.
All operations in a transformer are impartial of the sequence dimension—besides, crucially, consideration. In consequence, the eye operation must be modified to enter and output partial sequences. We parallelize consideration heads throughout many GPUs, which necessitates communication operations (all-to-alls) to maneuver tokens to the proper GPUs for processing. Previous to the eye operation, every GPU has a part of each sequence, however every consideration head should function on a full sequence. Within the instance proven in Determine 2, the primary GPU will get despatched all of the inputs for simply the primary consideration head, and the second GPU will get despatched all of the inputs for the second consideration head. After the eye operation, the outputs are despatched again to their authentic GPUs.
With sequence parallelism, we’re capable of present full-context-length Llama 3.1 fine-tuning, enabling customized fashions to know and purpose throughout a big context.
Optimizing Wonderful-tuning Efficiency
Customized optimizations like sequence parallelism for fine-tuning require us to have fine-grained management over the underlying mannequin implementation. Such customization just isn’t potential solely with the prevailing Llama 3.1 modeling code in HuggingFace. Nevertheless, for ease of serving and exterior compatibility, the ultimate fine-tuned mannequin must be a Llama 3.1 HuggingFace mannequin checkpoint. Due to this fact, our fine-tuning answer have to be extremely optimizable for coaching, but in addition capable of produce an interoperable output mannequin.
To attain this, we convert HuggingFace Llama 3.1 fashions into an equal inner Llama illustration previous to coaching. We’ve extensively optimized this inner illustration for coaching effectivity, with enhancements similar to environment friendly kernels, selective activation checkpointing, efficient reminiscence use, and sequence ID consideration masking. In consequence, our inner Llama illustration permits sequence parallelism whereas yielding as much as 40% larger coaching throughput and requiring a 40% smaller reminiscence footprint. These enhancements in useful resource utilization translate to raised fashions for our prospects, because the means to iterate shortly helps allow higher mannequin high quality.
When coaching is completed, we convert the mannequin from the interior illustration again to HuggingFace format, guaranteeing that the saved artifact is straight away prepared for serving through our Provisioned Throughput providing. Determine 3 under reveals this complete pipeline.
Subsequent Steps
Get began fine-tuning Llama 3.1 at this time through the UI or programmatically in Python. With Mosaic AI Model Training, you may effectively customise high-quality and open supply fashions for your enterprise wants, and construct information intelligence. Learn our documentation (AWS, Azure) and go to our pricing page to get began with fine-tuning LLMs on Databricks.
