Thallo – Scheduling for High-Performance Large-scale Non-linear Least-Squares Solvers (SIGGRAPH 2021)

Thallo – Scheduling for High-Performance Large-scale Non-linear Least-Squares Solvers

Thallo is a domain-specific language (DSL) that generates tailored high-performance GPU solvers and schedules from a concise, high-level energy description without the hassle of manually constructing and maintaining tedious and error-prone solvers. Thallo code is compact, and exceeds state-of-the-art performance across diverse applications in graphics and vision.

Large-scale optimization problems at the core of many graphics, vision, and imaging applications are often implemented by hand in tedious and error-prone processes in order to achieve high performance (in particular on GPUs), despite recent developments in libraries and DSLs. At the same time, these hand-crafted solver implementations reveal that the key for high performance is a problem-specific schedule that enables efficient usage of the underlying hardware. We propose Thallo, a domain-specific language for large-scale non-linear least-squares optimization problems. Thallo takes as input a compact, shader-like representation of an energy function and a (potentially auto-generated) schedule, translating the combination into high performance

GPU solvers. Thallo can generate solvers from a large scheduling space, and thus able to handle a large set of large-scale non-linear and non-smooth problems with various degrees of non-locality and compute-to-memory ratios, including diverse applications such as bundle adjustment, face blendshape fitting, and spatially-varying Poisson deconvolution. Abstracting schedules from the optimization, we outperform state-of-the-art GPU-based optimization DSLs by an average of 16× across all applications introduced in this work, and even some published hand-written GPU solvers by 30%+.