Stanford MLSys Seminar

Dan Fu - An ideal learned representation should display transferability and robustness. Supervised contrastive learning is a promising method for training accurate models, but produces representations that do not capture these properties due to class collapse -- when all points in a class map to the same representation. In this talk, we discuss how to alleviate these problems to improve the geometry of supervised contrastive learning. We identify two key principles: balancing the right amount of geometric "spread" in the embedding space, and inducing an inductive bias towards subclass clustering. We introduce two mechanisms for achieving these aims in supervised contrastive learning, and show that doing so improves transfer learning and worst-group robustness. Next, we show how we can apply these insights to improve entity retrieval in open-domain NLP tasks (e.g., QA, search). We present a new method, TABi, that trains bi-encoders with a type-aware supervised contrastive loss and improves long-tailed entity retrieval.

Kexin Rong - Learned Indexing and Sampling for Improving Query Performance in Big-Data Analytics Traditional data analytics systems improve query efficiency via fine-grained, row-level indexing and sampling techniques. However, to keep up with the data volumes, increasingly many systems store and process datasets in large partitions containing hundreds of thousands of rows. Therefore, these analytics systems must adapt traditional techniques to work with coarse-grained data partitions as a basic unit to process queries efficiently. In this talk, I will discuss two related ideas that combine learning techniques with partitioning designs to improve the query efficiency in the analytics systems. First, I will describe PS3, the first approximate query processing system that supports non-uniform, partition-level samples. PS3 reduces the number of partitions accessed by 3 to 70x to achieve the same error compared to a uniform sample of the partitions. Next, I will present OLO, an online learning framework that dynamically adapts data organization according to changes in query workload to minimize overall data access and movement. We show that dynamic reorganization outperforms a single, optimized partitioning scheme by up to 30% in end-to-end runtime. I will conclude by discussing additional open problems in this area.

Igor Markov - Looper: an end-to-end ML platform for product decisions Episode 60 of the Stanford MLSys Seminar Series!  Looper: an end-to-end ML platform for product decisions Speaker: Igor Markov  Abstract: Modern software systems and products increasingly rely on machine learning models to make data-driven decisions based on interactions with users, infrastructure and other systems. For broader adoption, this practice must (i) accommodate product engineers without ML backgrounds, (ii) support fine-grain product-metric evaluation and (iii) optimize for product goals. To address shortcomings of prior platforms, we introduce general principles for and the architecture of an ML platform, Looper, with simple APIs for decision-making and feedback collection. Looper covers the end-to-end ML lifecycle from collecting training data and model training to deployment and inference, and extends support to personalization, causal evaluation with heterogenous treatment effects, and Bayesian tuning for product goals. During the 2021 production deployment Looper simultaneously hosted 440-1,000 ML models that made 4-6 million real-time decisions per second. We sum up experiences of platform adopters and describe their learning curve.

Zhuohan Li - Alpa: Automated Model-Parallel Deep Learning Alpa (https://github.com/alpa-projects/alpa) automates model-parallel training of large deep learning models by generating execution plans that unify data, operator, and pipeline parallelism. Alpa distributes the training of large deep learning models by viewing parallelisms as two hierarchical levels: inter-operator and intra-operator parallelisms. Based on it, Alpa constructs a new hierarchical space for massive model-parallel execution plans. Alpa designs a number of compilation passes to automatically derive the optimal parallel execution plan in each independent parallelism level and implements an efficient runtime to orchestrate the two-level parallel execution on distributed compute devices. Alpa generates parallelization plans that match or outperform hand-tuned model-parallel training systems even on models they are designed for. Unlike specialized systems, Alpa also generalizes to models with heterogeneous architectures and models without manually-designed plans.

Shruti Bhosale - Scaling Multilingual Machine Translation to Thousands of Language Directions Existing work in translation has demonstrated the potential of massively multilingual machine translation by training a single model able to translate between any pair of languages. However, much of this work is English-Centric by training only on data which was translated from or to English. While this is supported by large sources of training data, it does not reflect translation needs worldwide. In this talk, I will describe how we create a true Many-to-Many multilingual translation model that can translate directly between any pair of 100 languages. We build and open source a training dataset that covers thousands of language directions with supervised data, created through large-scale mining. Then, we explore how to effectively increase model capacity through a combination of dense scaling and language-specific sparse parameters to create high quality models. Our focus on non-English-Centric models brings gains of more than 10 BLEU when directly translating between non-English directions while performing competitively to the best single systems of WMT.

Vijay Janapa Reddi - Tiny Machine Learning Tiny machine learning (TinyML) is a fast-growing field at the intersection of ML algorithms and low-cost embedded systems. TinyML enables on-device analysis of sensor data (vision, audio, IMU, etc.) at ultra-low-power consumption (less than 1mW). Processing data close to the sensor allows for an expansive new variety of always-on ML use-cases that preserve bandwidth, latency, and energy while improving responsiveness and maintaining privacy. This talk introduces the vision behind TinyML and showcases some of the interesting applications that TinyML is enabling in the field, from wildlife conservation to supporting public health initiatives. Yet, there are still numerous technical hardware and software challenges to address. Tight memory and storage constraints, MCU heterogeneity, software fragmentation and a lack of relevant large-scale datasets pose a substantial barrier to developing TinyML applications. To this end, the talk touches upon some of the research opportunities for unlocking the full potential of TinyML.

Fait Poms - A vision for interactive model development: efficient machine learning by bringing domain experts in the loop Building computer vision models today is an exercise in patience--days to weeks for human annotators to label data, hours to days to train and evaluate models, weeks to months of iteration to reach a production model. Without tolerance for this timeline or access to the massive compute and human resources required, building an accurate model can be challenging if not impossible. In this talk, we discuss a vision for interactive model development with iteration cycles of minutes, not weeks. We believe the key to this is integrating the domain expert at key points in the model building cycle and leveraging supervision cues above just example-level annotation. We will discuss our recent progress toward aspects of this goal: judiciously choosing when to use the machine and when to use the domain expert for fast, low label budget model training (CVPR 2021, ICCV 2021), building confidence in model performance with low-shot validation (ICCV 2021 Oral), and some initial tools for rapidly defining correctness criteria.

Travis Addair - Horovod and the Evolution of Deep Learning at Scale Deep neural networks are pushing the state of the art in numerous machine learning research domains; from computer vision, to natural language processing, and even tabular business data.  However, scaling such models to train efficiently on large datasets imposes a unique set of challenges that traditional batch data processing systems were not designed to solve.  Horovod is an open source framework that scales models written in TensorFlow, PyTorch, and MXNet to train seamlessly on hundreds of GPUs in parallel.  In this talk, we'll explain the concepts and unique constraints that led to the development of Horovod at Uber, and discuss how the latest trends in deep learning research are informing the future direction of the project within the Linux Foundation.  We'll explore how Horovod fits into production ML workflows in industry, and how tools like Spark and Ray can combine with Horovod to make productionizing deep learning at scale on remote data centers as simple as running locally on your laptop.  Finally, we'll share some thoughts on what's next for large scale deep learning, including new distributed training architectures and how the larger ecosystem of production ML tooling is evolving.

Doris Lee - Always-on Dataframe Visualizations with Lux Visualizations help data scientists discover trends, patterns, identify outliers, and derive insights from their data. However, existing visualization libraries in Python require users to write a substantial amount of code for plotting even a single visualization, often hindering the flow of data exploration. In this talk, you will learn about Lux, a lightweight visualization tool on top of pandas dataframes. Lux recommends visualizations for free to users as they explore their data within a Jupyter notebook without the need to write additional code. Lux is used by data scientists across a variety of industries and sectors and has nearly 66k total downloads and over 3.3k stars on GitHub. For more information, see: https://github.com/lux-org/lux.

Song Han - TinyML: Reducing the Carbon Footprint of Artificial Intelligence in the Internet of Things (IoT) Deep learning is computation-hungry and data-hungry. We aim to improve the computation efficiency and data efficiency of deep learning. I will first talk about MCUNet[1] that brings deep learning to IoT devices. The technique is tiny neural architecture search (TinyNAS) co-designed with a tiny inference engine (TinyEngine), enabling ImageNet-scale inference on an IoT device with only 1MB of FLASH. Next I will talk about TinyTL[2] that enables on-device training, reducing the memory footprint by 7-13x.  Finally, I will describe Differentiable Augmentation[3] that enables data-efficient GAN training, generating photo-realistic images using only 100 images, which used to require tens of thousand of images. We hope such TinyML techniques can make AI greener, faster, and more sustainable.