@article{20704,
  abstract     = {Generative models have advanced significantly in sampling material systems with continuous variables, such as atomistic structures. However, their application to discrete variables, like atom types or spin states, remains underexplored. In this work, we introduce a discrete flow matching model, tailored for systems with discrete phase-space coordinates (e.g., the Ising model or a multicomponent system on a lattice). This approach enables a single model to sample free energy surfaces over a wide temperature range with minimal training overhead, and the model generation is scalable to larger lattice sizes than those in the training set. We demonstrate our approach on the 2D Ising model, showing efficient and reliable free energy sampling. These results highlight the potential of flow matching for low-cost, scalable free energy sampling in discrete systems and suggest promising extensions to alchemical degrees of freedom in crystalline materials. The codebase developed for this work is openly available at https://github.com/tuoping/alchemicalFES.},
  author       = {Tuo, Ping and Zeng, Zezhu and Chen, Jiale and Cheng, Bingqing},
  issn         = {1549-9626},
  journal      = {Journal of Chemical Theory and Computation},
  number       = {22},
  pages        = {11427--11435},
  publisher    = {American Chemical Society},
  title        = {{Scalable multitemperature free energy sampling of classical Ising spin states}},
  doi          = {10.1021/acs.jctc.5c01248},
  volume       = {21},
  year         = {2025},
}

@inproceedings{22826,
  abstract     = {Large Language Models (LLMs) have demonstrated the ability to tackle increasingly complex tasks through advanced reasoning, long-form content generation,
and tool use. Solving these tasks often involves long inference-time computations.
In human problem solving, a common strategy to expedite work is collaboration: by
dividing the problem into sub-tasks, exploring different strategies concurrently, etc.
Recent research has shown that LLMs can also operate in parallel by implementing
explicit cooperation frameworks, such as voting mechanisms or the explicit creation of independent sub-tasks that can be executed in parallel. However, each of
these frameworks may not be suitable for all types of tasks, which can hinder their
applicability. In this work, we propose a different design approach: we run LLM
“workers” in parallel , allowing them to synchronize via a concurrently-updated
attention cache and prompt these workers to decide how best to collaborate. Our
approach allows the LLM instances to come up with their own collaboration strategy for the problem at hand, all the while “seeing” each other’s memory in the
concurrent KV cache. We implement this approach via Hogwild! Inference: a
parallel LLM inference engine where multiple instances of the same LLM run in
parallel with the same attention cache, with “instant” access to each other’s memory.1 Hogwild! Inference takes advantage of Rotary Position Embeddings (RoPE)
to avoid recomputation while improving parallel hardware utilization. We find that
modern reasoning-capable LLMs can perform inference with shared Key-Value
cache out of the box, without additional fine-tuning.},
  author       = {Rodionov, Gleb and Garipov, Roman and Shutova, Alina and Yakushev, George and Schultheis, Erik and Egiazarian, Vage and Sinitsin, Anton and Kuznedelev, Denis and Alistarh, Dan-Adrian},
  booktitle    = {39th Conference on Neural Information Processing Systems},
  isbn         = {9798331338275},
  issn         = {1049-5258},
  location     = {San Diego, CA, United States},
  pages        = {52014--52055},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{Hogwild! Inference: Parallel LLM generation via concurrent attention}},
  doi          = {10.52202/085713-1551},
  volume       = {38},
  year         = {2025},
}

@inproceedings{22830,
  abstract     = {We introduce AutoJudge, a method that accelerates large language model (LLM) inference with task-specific lossy speculative decoding. Instead of matching the original model output distribution token-by-token, we identify the generated tokens that affect the downstream quality of the response, relaxing the distribution match guarantee so that the "unimportant" tokens can be generated faster. Our approach relies on a semi‑greedy search algorithm to test which of the mismatches between target and draft models should be corrected to preserve quality and which ones may be skipped. We then train a lightweight classifier based on existing LLM embeddings to predict, at inference time, which mismatching tokens can be safely accepted without compromising the final answer quality. We evaluate AutoJudge with multiple draft/target model pairs on mathematical reasoning and programming benchmarks, achieving significant speedups at the cost of a minor accuracy reduction. Notably, on GSM8K with the Llama 3.1 70B target model, our approach achieves up to 
≈
2
×
 speedup \textit{over speculative decoding} at the cost of a 
≤
1
%
 drop in accuracy. When applied to the LiveCodeBench benchmark, AutoJudge automatically detects programming-specific important tokens, accepting 
≥
25
 tokens per speculation cycle at a
 
2
%
 drop in Pass@1. Our approach requires no human annotation and is easy to integrate with modern LLM inference frameworks.},
  author       = {Garipov, Roman and Velikonivtsev, Fedor and Ermakov, Ivan and Svirschevski, Ruslan and Egiazarian, Vage and Ryabinin, Max},
  booktitle    = {39th Annual Conference on Neural Information Processing Systems},
  isbn         = {9798331338275},
  issn         = {1049-5258},
  location     = {San Diego, CA, United States},
  pages        = {104904--104941},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{AutoJudge: Judge decoding without manual annotation}},
  doi          = {10.52202/085713-3163},
  volume       = {38},
  year         = {2025},
}

@inproceedings{15011,
  abstract     = {Pruning large language models (LLMs) from the BERT family has emerged as a standard compression benchmark, and several pruning methods have been proposed for this task. The recent “Sparsity May Cry” (SMC) benchmark put into question the validity of all existing methods, exhibiting a more complex setup where many known pruning methods appear to fail. We revisit the question of accurate BERT-pruning during fine-tuning on downstream datasets, and propose a set of general guidelines for successful pruning, even on the challenging SMC benchmark. First, we perform a cost-vs-benefits analysis of pruning model components, such as the embeddings and the classification head; second, we provide a simple-yet-general way of scaling training, sparsification and learning rate schedules relative to the desired target sparsity; finally, we investigate the importance of proper parametrization for Knowledge Distillation in the context of LLMs. Our simple insights lead to state-of-the-art results, both on classic BERT-pruning benchmarks, as well as on the SMC benchmark, showing that even classic gradual magnitude pruning (GMP) can yield competitive results, with the right approach.},
  author       = {Kurtic, Eldar and Hoefler, Torsten and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of Machine Learning Research},
  issn         = {2640-3498},
  location     = {Hongkong, China},
  pages        = {542--553},
  publisher    = {ML Research Press},
  title        = {{How to prune your language model: Recovering accuracy on the "Sparsity May Cry" benchmark}},
  volume       = {234},
  year         = {2024},
}

@inproceedings{17093,
  abstract     = {Federated Learning (FL) enables large-scale distributed training of machine learning models, while still allowing individual nodes to maintain data locally. However, executing FL at scale comes with inherent practical challenges: 1) heterogeneity of the local node data distributions, 2) heterogeneity of node computational speeds (asynchrony), but also 3) constraints in the amount of communication between the clients and the server. In this work, we present the first variant of the classic federated averaging (FedAvg) algorithm which, at the same time, supports data heterogeneity, partial client asynchrony, and communication compression. Our algorithm comes with a novel, rigorous analysis showing that, in spite of these system relaxations, it can provide similar convergence to FedAvg in interesting parameter regimes. Experimental results in the rigorous LEAF benchmark on setups of up to 300 nodes show that our algorithm ensures fast convergence for standard federated tasks, improving upon prior quantized and asynchronous approaches.},
  author       = {Zakerinia, Hossein and Talaei, Shayan and Nadiradze, Giorgi and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of the 27th International Conference on Artificial Intelligence and Statistics},
  issn         = {2640-3498},
  location     = {Valencia, Spain},
  pages        = {3448--3456},
  publisher    = {ML Research Press},
  title        = {{Communication-efficient federated learning with data and client heterogeneity}},
  volume       = {238},
  year         = {2024},
}

@inproceedings{18975,
  abstract     = {Leveraging second-order information about the loss at the scale of deep networks is one of the main lines of approach for improving the performance of current optimizers for deep learning. Yet, existing approaches for accurate full-matrix preconditioning, such as Full-Matrix Adagrad (GGT) or Matrix-Free Approximate Curvature (M-FAC) suffer from massive storage costs when applied even to small-scale models, as they must store a sliding window of gradients, whose memory requirements are multiplicative in the model dimension. In this paper, we address this issue via a novel and efficient error-feedback technique that can be applied to compress preconditioners by up to two orders of magnitude in practice, without loss of convergence. Specifically, our approach compresses the gradient information via sparsification or low-rank compression before it is fed into the preconditioner, feeding the compression error back into future iterations. Extensive experiments on deep neural networks show that this approach can compress full-matrix preconditioners to up to 99% sparsity without accuracy loss, effectively removing the memory overhead of fullmatrix preconditioners such as GGT and M-FAC.},
  author       = {Modoranu, Ionut-Vlad and Kalinov, Aleksei and Kurtic, Eldar and Frantar, Elias and Alistarh, Dan-Adrian},
  booktitle    = {41st International Conference on Machine Learning},
  issn         = {2640-3498},
  location     = {Vienna, Austria},
  pages        = {35910--35933},
  publisher    = {ML Research Press},
  title        = {{Error feedback can accurately compress preconditioners}},
  volume       = {235},
  year         = {2024},
}

@inproceedings{18976,
  abstract     = {We analyze asynchronous-type algorithms for distributed SGD in the heterogeneous setting, where each worker has its own computation and communication speeds, as well as data distribution. In these algorithms, workers compute possibly stale and stochastic gradients associated with their local data at some iteration back in history and then return those gradients to the server without synchronizing with other workers. We present a unified convergence theory for non-convex smooth functions in the heterogeneous regime. The proposed analysis provides convergence for pure asynchronous SGD and its various modifications. Moreover, our theory explains what affects the convergence rate and what can be done to improve the performance of asynchronous algorithms. In particular, we introduce a novel asynchronous method based on worker shuffling. As a by-product of our analysis, we also demonstrate convergence guarantees for gradient-type algorithms such as SGD with random reshuffling and shuffle-once mini-batch SGD. The derived rates match the best-known results for those algorithms, highlighting the tightness of our approach. Finally, our numerical evaluations support theoretical findings and show the good practical performance of our method.},
  author       = {Islamov, Rustem and Safaryan, Mher and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of The 27th International Conference on Artificial Intelligence and Statistics},
  issn         = {2640-3498},
  location     = {Valencia, Spain},
  pages        = {649--657},
  publisher    = {ML Research Press},
  title        = {{AsGrad: A sharp unified analysis of asynchronous-SGD algorithms}},
  volume       = {238},
  year         = {2024},
}

@inproceedings{18977,
  abstract     = {Recent advances in large language model (LLM) pretraining have led to high-quality LLMs with impressive abilities. By compressing such LLMs via quantization to 3-4 bits per parameter, they can fit into memory-limited devices such as laptops and mobile phones, enabling personalized use. Quantizing models to 3-4 bits per parameter can lead to moderate to high accuracy losses, especially for smaller models (1-10B parameters), which are suitable for edge deployment. To address this accuracy issue, we introduce the Sparse-Quantized Representation (SpQR), a new compressed format and quantization technique that enables for the first time \emph{near-lossless} compression of LLMs across model scales while reaching similar compression levels to previous methods. SpQR works by identifying and isolating \emph{outlier weights}, which cause particularly large quantization errors, and storing them in higher precision while compressing all other weights to 3-4 bits, and achieves relative accuracy losses of less than 
 in perplexity for highly-accurate LLaMA and Falcon LLMs. This makes it possible to run a 33B parameter LLM on a single 24 GB consumer GPU without performance degradation at 15% speedup, thus making powerful LLMs available to consumers without any downsides. SpQR comes with efficient algorithms for both encoding weights into its format, as well as decoding them efficiently at runtime. Specifically, we provide an efficient GPU inference algorithm for SpQR, which yields faster inference than 16-bit baselines at similar accuracy while enabling memory compression gains of more than 4x.},
  author       = {Dettmers, Tim and Svirschevski, Ruslan A. and Egiazarian, Vage and Kuznedelev, Denis and Frantar, Elias and Ashkboos, Saleh and Borzunov, Alexander and Hoefler, Torsten and Alistarh, Dan-Adrian},
  booktitle    = {12th International Conference on Learning Representations},
  location     = {Vienna, Austria},
  publisher    = {OpenReview},
  title        = {{SpQR: A sparse-quantized representation for near-lossless LLM weight compression}},
  year         = {2024},
}

@inproceedings{19510,
  abstract     = {We propose a new variant of the Adam optimizer [Kingma and Ba, 2014] called
MICROADAM that specifically minimizes memory overheads, while maintaining
theoretical convergence guarantees. We achieve this by compressing the gradient
information before it is fed into the optimizer state, thereby reducing its memory
footprint significantly. We control the resulting compression error via a novel
instance of the classical error feedback mechanism from distributed optimization [Seide et al., 2014, Alistarh et al., 2018, Karimireddy et al., 2019] in which
the error correction information is itself compressed to allow for practical memory
gains. We prove that the resulting approach maintains theoretical convergence
guarantees competitive to those of AMSGrad, while providing good practical performance. Specifically, we show that MICROADAM can be implemented efficiently
on GPUs: on both million-scale (BERT) and billion-scale (LLaMA) models, MICROADAM provides practical convergence competitive to that of the uncompressed
Adam baseline, with lower memory usage and similar running time. Our code is
available at https://github.com/IST-DASLab/MicroAdam.},
  author       = {Modoranu, Ionut-Vlad and Safaryan, Mher and Malinovsky, Grigory and Kurtic, Eldar and Robert, Thomas and Richtárik, Peter and Alistarh, Dan-Adrian},
  booktitle    = {38th Conference on Neural Information Processing Systems},
  issn         = {1049-5258},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{MICROADAM: Accurate adaptive optimization with low space overhead and provable convergence}},
  volume       = {37},
  year         = {2024},
}

@inproceedings{19511,
  abstract     = {We introduce QuaRot, a new Quantization scheme based on Rotations, which is able to quantize LLMs end-to-end, including all weights, activations, and KV cache in 4 bits. QuaRot rotates LLMs in a way that removes outliers from the hidden state without changing the output, making quantization easier. This computational invariance is applied to the hidden state (residual) of the LLM, as well as to the activations of the feed-forward components, aspects of the attention mechanism, and to the KV cache. The result is a quantized model where all matrix multiplications are performed in 4 bits, without any channels identified for retention in higher precision. Our 4-bit quantized LLAMA2-70B model has losses of at most 0.47 WikiText-2 perplexity and retains 99% of the zero-shot performance. We also show that QuaRot can provide lossless 6 and 8 bit LLAMA-2 models without any calibration data using round-to-nearest quantization. Code is available at github.com/spcl/QuaRot.},
  author       = {Ashkboos, Saleh and Mohtashami, Amirkeivan and Croci, Maximilian L. and Li, Bo and Cameron, Pashmina and Jaggi, Martin and Alistarh, Dan-Adrian and Hoefler, Torsten and Hensman, James},
  booktitle    = {38th Conference on Neural Information Processing Systems},
  issn         = {1049-5258},
  location     = {Vancouver, Canada},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{QuaRot: Outlier-free 4-bit inference in rotated LLMs}},
  volume       = {37},
  year         = {2024},
}

@inproceedings{19518,
  abstract     = {The rising footprint of machine learning has led to a focus on imposing model
sparsity as a means of reducing computational and memory costs. For deep neural
networks (DNNs), the state-of-the-art accuracy-vs-sparsity is achieved by heuristics
inspired by the classical Optimal Brain Surgeon (OBS) framework [LeCun et al.,
1989, Hassibi and Stork, 1992, Hassibi et al., 1993], which leverages loss curvature
information to make better pruning decisions. Yet, these results still lack a solid
theoretical understanding, and it is unclear whether they can be improved by
leveraging connections to the wealth of work on sparse recovery algorithms. In this
paper, we draw new connections between these two areas and present new sparse
recovery algorithms inspired by the OBS framework that comes with theoretical
guarantees under reasonable assumptions and have strong practical performance.
Specifically, our work starts from the observation that we can leverage curvature
information in OBS-like fashion upon the projection step of classic iterative sparse
recovery algorithms such as IHT. We show for the first time that this leads both
to improved convergence bounds under standard assumptions. Furthermore, we
present extensions of this approach to the practical task of obtaining accurate sparse
DNNs, and validate it experimentally at scale for Transformer-based models on
vision and language tasks.},
  author       = {Wu, Diyuan and Modoranu, Ionut-Vlad and Safaryan, Mher and Kuznedelev, Denis and Alistarh, Dan-Adrian},
  booktitle    = {38th Conference on Neural Information Processing Systems},
  issn         = {1049-5258},
  location     = {Vancouver, Canada},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{The iterative optimal brain surgeon: Faster sparse recovery by leveraging second-order information}},
  volume       = {37},
  year         = {2024},
}

@inproceedings{19519,
  abstract     = {There has been significant interest in "extreme" compression of large language models (LLMs), i.e. to 1-2 bits per parameter, which allows such models to be executed efficiently on resource-constrained devices. Existing work focused on improved one-shot quantization techniques and weight representations; yet, purely post-training approaches are reaching diminishing returns in terms of the accuracy-vs-bit-width trade-off. State-of-the-art quantization methods such as QuIP# and AQLM include fine-tuning (part of) the compressed parameters over a limited amount of calibration data; however, such fine-tuning techniques over compressed weights often make exclusive use of straight-through estimators (STE), whose performance is not well-understood in this setting. In this work, we question the use of STE for extreme LLM compression, showing that it can be sub-optimal, and perform a systematic study of quantization-aware fine-tuning strategies for LLMs.We propose PV-Tuning - a representation-agnostic framework that generalizes and improves upon existing fine-tuning strategies, and provides convergence guarantees in restricted cases.On the practical side, when used for 1-2 bit vector quantization, PV-Tuning outperforms prior techniques for highly-performant models such as Llama and Mistral. Using PV-Tuning, we achieve the first Pareto-optimal quantization for Llama-2 family models at 2 bits per parameter.},
  author       = {Malinovskii, Vladimir and Mazur, Denis and Ilin, Ivan and Kuznedelev, Denis and Burlachenko, Konstantin and Yi, Kai and Alistarh, Dan-Adrian and Richtarik, Peter},
  booktitle    = {38th Conference on Neural Information Processing Systems},
  isbn         = {9798331314385},
  issn         = {1049-5258},
  location     = {Vancouver, Canada},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{PV-tuning: Beyond straight-through estimation for extreme LLM compression}},
  volume       = {37},
  year         = {2024},
}

@misc{19884,
  abstract     = {This is Marlin, a Mixed Auto-Regressive Linear kernel (and the name of one of the planet's fastest fish), an extremely optimized FP16xINT4 matmul kernel aimed at LLM inference that can deliver close to ideal (4x) speedups up to batchsizes of 16-32 tokens (in contrast to the 1-2 tokens of prior work with comparable speedup).

Additionally, it includes Sparse-Marlin, an extension of the MARLIN kernels adding support to 2:4 weight sparsity, achieving 5.3x speedups on NVIDIA GPUs (Ampere/Ada).},
  author       = {Frantar, Elias and Castro, Roberto and Chen, Jiale and Hoefler, Torsten and Alistarh, Dan-Adrian},
  publisher    = {Zenodo},
  title        = {{MARLIN: Mixed-precision auto-regressive parallel inference on Large Language Models}},
  doi          = {10.5281/ZENODO.14213091},
  year         = {2024},
}

@inproceedings{17329,
  abstract     = {We initiate the study of game dynamics in the population protocol model: n agents each maintain a current local strategy and interact in pairs uniformly at random. Upon each interaction, the agents play a two-person game and receive a payoff from an underlying utility function, and they can subsequently update their strategies according to a fixed local algorithm. In this setting, we ask how the distribution over agent strategies evolves over a sequence of interactions, and we introduce a new distributional equilibrium concept to quantify the quality of such distributions. As an initial example, we study a class of repeated prisoner's dilemma games, and we consider a family of simple local update algorithms that yield non-trivial dynamics over the distribution of agent strategies. We show that these dynamics are related to a new class of high-dimensional Ehrenfest random walks, and we derive exact characterizations of their stationary distributions, bounds on their mixing times, and prove their convergence to approximate distributional equilibria. Our results highlight trade-offs between the local state space of each agent, and the convergence rate and approximation factor of the underlying dynamics. Our approach opens the door towards the further characterization of equilibrium computation for other classes of games and dynamics in the population setting.},
  author       = {Alistarh, Dan-Adrian and Chatterjee, Krishnendu and Karrabi, Mehrdad and Lazarsfeld, John M},
  booktitle    = {Proceedings of the 43rd Annual ACM Symposium on Principles of Distributed Computing},
  isbn         = {9798400706684},
  location     = {Nantes, France},
  pages        = {40--49},
  publisher    = {Association for Computing Machinery},
  title        = {{Game dynamics and equilibrium computation in the population protocol model}},
  doi          = {10.1145/3662158.3662768},
  year         = {2024},
}

@inproceedings{17332,
  abstract     = {Tree data structures, such as red-black trees, quad trees, treaps, or tries, are fundamental tools in computer science. A classical problem in concurrency is to obtain expressive, efficient, and scalable versions of practical tree data structures. We are interested in concurrent trees supporting range queries, i.e., queries that involve multiple consecutive data items. Existing implementations with this capability can list keys in a specific range, but do not support aggregate range queries: for instance, if we want to calculate the number of keys in a range, the only choice is to retrieve a whole list and return its size. This is suboptimal: in the sequential setting, one can augment a balanced search tree with counters and, consequently, perform these aggregate requests in logarithmic rather than linear time.In this paper, we propose a generic approach to implement a broad class of range queries on concurrent trees in a way that is wait-free, asymptotically efficient, and practically scalable. The key idea is a new mechanism for maintaining metadata concurrently at tree nodes, which can be seen as a wait-free variant of hand-over-hand locking (which we call hand-over-hand helping). We did a preliminary implementation of the wait-free binary search tree and preliminary experiments have indicated the soundness of our approach.},
  author       = {Kokorin, Ilya and Yudov, Victor and Aksenov, Vitaly and Alistarh, Dan-Adrian},
  booktitle    = {2024 IEEE International Parallel and Distributed Processing Symposium},
  isbn         = {9798350337662},
  issn         = {1530-2075},
  location     = {San Francisco, CA, United States},
  pages        = {169--179},
  publisher    = {IEEE},
  title        = {{Wait-free trees with asymptotically-efficient range queries}},
  doi          = {10.1109/IPDPS57955.2024.00023},
  year         = {2024},
}

@inproceedings{17456,
  abstract     = {Data-parallel distributed training of deep neural networks (DNN) has gained very widespread adoption, but can still experience communication bottlenecks. To address this issue, entire families of compression mechanisms have been developed, including quantization, sparsification, and low-rank approximation, some of which are seeing significant practical adoption. Despite this progress, almost all known compression schemes apply compression uniformly across DNN layers, although layers are heterogeneous in terms of parameter count and their impact on model accuracy.In this work, we provide a general framework for adapting the degree of compression across the model's layers dynamically during training, improving the overall compression, while leading to substantial speedups, without sacrificing accuracy. Our framework, called L-GreCo, is based on an adaptive algorithm, which automatically picks the optimal compression parameters for model layers guaranteeing the best compression ratio while satisfying an error constraint. Extensive experiments over image classification and language modeling tasks shows that L-GreCo is effective across all existing families of compression methods, and achieves up to 2.5
×
 training speedup and up to 5
×
 compression improvement over efficient implementations of existing approaches, while recovering full accuracy. Moreover, L-GreCo is complementary to existing adaptive algorithms, improving their compression ratio by 50\% and practical throughput by 66\%. An anonymized implementation is available at https://github.com/LGrCo/L-GreCo.},
  author       = {Markov, Ilia and Alimohammadi, Kaveh and Frantar, Elias and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of Machine Learning and Systems },
  editor       = {Gibbons, P. and Pekhimenko, G. and De Sa, C.},
  location     = {Athens, Greece},
  publisher    = {Association for Computing Machinery},
  title        = {{L-GreCo: Layerwise-adaptive gradient compression for efficient data-parallel deep learning}},
  volume       = {6},
  year         = {2024},
}

@phdthesis{17490,
  abstract     = {Deep learning is essential in numerous applications nowadays, with many recent advancements made possible by training very large models. Despite their broad applicability, training neural networks is often time-intensive, and it is usually impractical to manage large models and datasets on a single machine. To address these issues, distributed deep learning training has become increasingly important. However, distributed training requires synchronization among nodes, and the mini-batch stochastic gradient descent algorithm places a significant load on network connections. A possible solution to tackle the synchronization bottleneck is to reduce a message size by lossy compression.

In this thesis, we investigate systems and algorithmic approaches to communication compression during training. From the systems perspective, we demonstrate that a common approach of expensive hardware overprovisioning can be replaced through a thorough system design. We introduce a framework that introduces efficient software support for compressed communication in machine learning applications, applicable to both multi-GPU single-node training and larger-scale multi-node training. Our framework integrates with popular ML frameworks, providing up to 3x speedups for multi-GPU nodes based on commodity hardware and order-of-magnitude improvements in the multi-node setting, with negligible impact on accuracy.

Also, we consider an application of our framework to different communication schemes, such as Fully Sharded Data Parallel. We provide strong convergence guarantees for the compression in such a setup. Empirical validation shows that our method preserves model accuracy for GPT-family models with up to 1.3 billion parameters, while completely removing the communication bottlenecks of non-compressed alternatives, providing up to 2.2x speedups end-to-end.

From the algorithmic side, we propose a general framework that dynamically adjusts the degree of compression across a model's layers during training. This approach enhances overall compression and results in significant speedups without compromising accuracy. Our algorithm utilizes an adaptive algorithm that automatically selects the optimal compression parameters for model layers, ensuring the best compression ratio while adhering to an error constraint. Our method is effective across all existing families of compression methods. It achieves up to 2.5x faster training and up to a 5x improvement in compression compared to efficient implementations of current approaches. Additionally, LGreCo can complement existing adaptive algorithms.
},
  author       = {Markov, Ilia},
  issn         = {2663-337X},
  pages        = {102},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Communication-efficient distributed training of deep neural networks : An algorithms and systems perspective}},
  doi          = {10.15479/at:ista:17490},
  year         = {2024},
}

@inproceedings{18070,
  abstract     = {Parallel SGD in a shared-memory setting is oft-represented by the popular Hogwild! algorithm, in which lock-free updates are asynchronously performed by multiple computing processes. Unfortunately, scaling Hogwild! to distributed workers is largely unexplored. Specifically, it is unknown if any adaptation of Hogwild! to the popular decentralized multi-GPU setting offers any competitive speedup, either empirically or theoretically. In this work, we investigate the potential of decentralizing Hogwild! by incorporating simultaneously (a) asynchronous local gradient updates on the shared memory of GPUs, and (b) non-blocking asynchronous decentralized federated averaging. A naive direct implementation shows degradation in performance, arising from scheduling overheads and concurrent write conflicts on GPUs. To mitigate these drawbacks, we investigate and propose a new method, based on careful block selection rules, which update only portions of the parameter vectors. Our experiments show that the resulting decentralized training method exhibits improved throughput and competitive accuracy for standard image classification benchmarks on the CIFAR-10, CIFAR-100, and Imagenet datasets. On the theoretical side, we prove that our method guarantees sublinear ergodic convergence rates for non-convex objectives.},
  author       = {Chatterjee, Bapi and Kungurtsev, Vyacheslav and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of the 44th International Conference on Distributed Computing Systems},
  isbn         = {9798350386059},
  issn         = {2575-8411},
  location     = {Jersey City, NJ, United States},
  pages        = {857--868},
  publisher    = {IEEE},
  title        = {{Federated SGD with local asynchrony}},
  doi          = {10.1109/ICDCS60910.2024.00084},
  year         = {2024},
}

@inproceedings{18113,
  abstract     = {The emergence of accurate open large language models (LLMs) has led to a race towards performant quantization techniques which can enable their execution on end-user devices. In this paper, we revisit the problem of “extreme” LLM compression—defined as targeting extremely low bit counts, such as 2 to 3 bits per parameter—from the point of view of classic methods in Multi-Codebook Quantization (MCQ). Our algorithm, called AQLM, generalizes the classic Additive Quantization (AQ) approach for information retrieval to advance the state-of-the-art in LLM compression, via two innovations: 1) learned additive quantization of weight matrices in input-adaptive fashion, and 2) joint optimization of codebook parameters across each transformer blocks. Broadly, AQLM is the first scheme that is Pareto optimal in terms of accuracy-vs-model-size when compressing to less than 3 bits per parameter, and significantly improves upon all known schemes in the extreme compression (2bit) regime. In addition, AQLM is practical: we provide fast GPU and CPU implementations of AQLM for token generation, which enable us to match or outperform optimized FP16 implementations for speed, while executing in a much smaller memory footprint.},
  author       = {Egiazarian, Vage and Panferov, Andrei and Kuznedelev, Denis and Frantar, Elias and Babenko, Artem and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of the 41st International Conference on Machine Learning},
  issn         = {2640-3498},
  location     = {Vienna, Austria},
  pages        = {12284--12303},
  publisher    = {ML Research Press},
  title        = {{Extreme compression of large language models via additive quantization}},
  volume       = {235},
  year         = {2024},
}

@inproceedings{18117,
  abstract     = {We investigate parameter-efficient fine-tuning (PEFT) methods that can provide good accuracy under limited computational and memory budgets in the context of large language models (LLMs). We present a new PEFT method called Robust Adaptation (RoSA) inspired by robust principal component analysis that jointly trains low-rank
 and highly-sparse components on top of a set of fixed pretrained weights to efficiently approximate the performance of a full-fine-tuning (FFT) solution. Across a series of challenging generative tasks such as grade-school math and SQL query generation, which require fine-tuning for good performance, we show that RoSA outperforms LoRA, pure sparse fine-tuning, and alternative hybrid methods at the same parameter budget, and can even recover the performance of FFT on some tasks. We provide system support for RoSA to complement the training algorithm, specifically in the form of sparse GPU kernels which enable memory- and computationally-efficient training, and show that it is also compatible with low-precision base weights, resulting in the first joint representation combining quantization, low-rank and sparse approximations. Our code is available at https://github.com/IST-DASLab/RoSA.},
  author       = {Nikdan, Mahdi and Tabesh, Soroush and Crncevic, Elvir and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of the 41st International Conference on Machine Learning},
  issn         = {2640-3498},
  location     = {Vienna, Austria},
  pages        = {38187--38206},
  publisher    = {ML Research Press},
  title        = {{RoSA: Accurate parameter-efficient fine-tuning via robust adaptation}},
  volume       = {235},
  year         = {2024},
}

