ML for Systems

Ballroom C

Moderator: Martin Maas


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Ballroom B - Position 30
AutoScratch: ML-Optimized Cache Management for Inference-Oriented GPUs

Yaosheng Fu · Evgeny Bolotin · Aamer Jaleel · Gal Dalal · Shie Mannor · Jacob Subag · Noam Korem · Michael Behar · David Nellans

Taking advantage of the L2 residency control mechanism introduced with NVIDIA's Ampere GPUs, we propose a Machine Learning (ML) based framework called AutoScratch to automatically discover and optimize the L2 residency for inference-oriented GPUs, effectively removing any human involvement from the optimization loop. AutoScratch bridges the gap between the performance of an explicitly controlled scratchpad memory and the convenience of a hardware-controlled cache. We develop two versions of AutoScratch, AutoScratch-RL harnessing reinforcement learning (RL) and AutoScratch-EA leveraging a state-of-the-art evolutionary algorithm (EA). We integrate AutoScratch with NVIDIA's TensorRT framework to fully automate the optimization pipeline for arbitrary DL inference applications. We evaluate AutoScratch on NVIDIA's L4 GPU silicon using MLPerf inference workloads and show that AutoScratch reduces off-chip DRAM traffic by 29% and improves the overall performance by 9% (up to 22%).

Ballroom B - Position 31
GiPH: Generalizable Placement Learning for Adaptive Heterogeneous Computing

Yi Hu · Chaoran Zhang · Edward Andert · Harshul Singh · Aviral Shrivastava · James Laudon · Yanqi Zhou · Bob Iannucci · Carlee Joe-Wong

Careful placement of a distributed computational application within a target device cluster is critical for achieving low application completion time. The problem is challenging due to its NP-hardness and combinatorial nature. In recent years, learning-based approaches have been proposed to learn a placement policy that can be applied to unseen applications, motivated by the problem of placing a neural network across cloud servers. These approaches, however, generally assume the device cluster is fixed, which is not the case in mobile or edge computing settings, where heterogeneous devices move in and out of range for a particular application. To address the challenge of scaling to different-sized device clusters and adapting to the addition of new devices, we propose a new learning approach called GiPH, which learns policies that generalize to dynamic device clusters via a novel graph representation gpNet that efficiently encodes the information needed for choosing a good placement, and a scalable graph neural network (GNN) that learns a summary of the gpNet information. GiPH turns the placement problem into that of finding a sequence of placement improvements, learning a policy for selecting this sequence that scales to problems of arbitrary size. We evaluate GiPH with a wide range of task graphs and device clusters and show that our learned policy rapidly finds good placements for new problem instances. GiPH finds placements that achieve up to 30.5% better makespan, searching up to 3 times faster than other search-based placement policies.

Ballroom B - Position 32
Learning to Parallelize with OpenMP by Augmented Heterogeneous AST Representation

Le Chen · Quazi Ishtiaque Mahmud · Hung Phan · Nesreen Ahmed · Ali Jannesari

Detecting parallelizable code regions is a challenging task, even for experienced developers. Numerous recent studies have explored the use of machine learning for code analysis and program synthesis, including parallelization, in light of the success of machine learning in natural language processing. However, applying machine learning techniques to parallelism detection presents several challenges, such as the lack of an adequate dataset for training, an effective code representation with rich information, and a suitable machine learning model to learn the latent features of code for diverse analyses. To address these challenges, we propose a novel graph-based learning approach called Graph2Par that utilizes a heterogeneous augmented abstract syntax tree (Augmented-AST) representation for code. The proposed approach primarily focused on loop-level parallelization with OpenMP. Moreover, we create an OMP_Serial dataset with 18598 parallelizable and 13972 non-parallelizable loops to train the machine learning models. Our results show that our proposed approach achieves the accuracy of parallelizable code region detection with 85\% accuracy and outperforms the state-of-the-art token-based machine learning approach. These results indicate that our approach is competitive with state-of-the-art tools and capable of handling loops with complex structures that other tools may overlook.

Ballroom B - Position 33
Outstanding Paper Award
Virtual Machine Allocation with Lifetime Predictions

Hugo Barbalho · Patricia Kovaleski · Beibin Li · Luke Marshall · Marco Molinaro · Abhisek Pan · Eli Cortez · Matheus Leao · Harsh Patwari · Zuzu Tang · Larissa Rozales Gonçalves · David Dion · Thomas Moscibroda · Ishai Menache

The emergence of machine learning technology has motivated the use of ML-based predictors in computer systems to improve their efficiency and robustness. However, there are still numerous algorithmic and systems challenges in effectively utilizing ML models in large-scale resource management services that require high throughput and response latency of milliseconds. In this paper, we describe the design and implementation of a VM allocation service that uses ML predictions of the VM lifetime to improve packing efficiencies. We design lifetime-aware placement algorithms that are provably robust to prediction errors and demonstrate their merits in extensive real-trace simulations. We significantly upgraded the VM allocation infrastructure of Microsoft Azure to support such algorithms that require ML inference in the critical path. A robust version of our algorithms has been recently deployed in production, and obtains efficiency improvements expected from simulations.