arXiv subjects

Gabriel Rodriguez-Canal

Publications and source records attributed to Gabriel Rodriguez-Canal.

7 recordsLinked to original sources

arXiv2026

Lifting to tensors when compiling scientific computing workloads for AI Engines

It has been demonstrated that specialised architectures, such as FPGAs and AMD's AI Engines (AIEs), have the potential to deliver energy and performance advantages for scientific computing. Given the integration of AIEs into AMD's CPUs, this is an interesting potential avenue especially when executing on the edge or making better use of local compute constrained resources. However, a major challenge is in enabling existing codes to run on this architecture without extensive modification. Put simply, it requires significant expertise and time to port codes to the AIE's execution model. In this paper we explore a compilation pipeline for efficiently mapping loops in general purpose, scientific codes to AIEs. Lifting the semantics of an application into tensors, we demonstrate that this is able to capture the intention of general purpose loops annotated with OpenMP and such high-level tensor information provides a richness that is effective when mapping to the AIEs. Requiring only an OpenMP decorated loop, our approach significantly reduces code complexity when targeting the architecture. For six kernel benchmarks, representing AI and scientific computing, using our approach the NPU performs comparatively to the multicore CPU for float32, in all cases at reduced energy to solution. For two scientific computing kernels running across both the CPU and NPU together delivers up to a 40% improvement in performance and 15% reduction in energy usage compared to the CPU alone.

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arXiv2025

An MLIR pipeline for offloading Fortran to FPGAs via OpenMP

With the slowing of Moore's Law, heterogeneous computing platforms such as Field Programmable Gate Arrays (FPGAs) have gained increasing interest for accelerating HPC workloads. In this work we present, to the best of our knowledge, the first implementation of selective code offloading to FPGAs via the OpenMP target directive within MLIR. Our approach combines the MLIR OpenMP dialect with a High-Level Synthesis (HLS) dialect to provide a portable compilation flow targeting FPGAs. Unlike prior OpenMP FPGA efforts that rely on custom compilers, by contrast we integrate with MLIR and so support any MLIR-compatible front end, demonstrated here with Flang. Building upon a range of existing MLIR building blocks significantly reduces the effort required and demonstrates the composability benefits of the MLIR ecosystem. Our approach supports manual optimisation of offloaded kernels through standard OpenMP directives, and this work establishes a flexible and extensible path for directive-based FPGA acceleration integrated within the MLIR ecosystem.

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arXiv2024

A shared compilation stack for distributed-memory parallelism in stencil DSLs

Domain Specific Languages (DSLs) increase programmer productivity and provide high performance. Their targeted abstractions allow scientists to express problems at a high level, providing rich details that optimizing compilers can exploit to target current- and next-generation supercomputers. The convenience and performance of DSLs come with significant development and maintenance costs. The siloed design of DSL compilers and the resulting inability to benefit from shared infrastructure cause uncertainties around longevity and the adoption of DSLs at scale. By tailoring the broadly-adopted MLIR compiler framework to HPC, we bring the same synergies that the machine learning community already exploits across their DSLs (e.g. Tensorflow, PyTorch) to the finite-difference stencil HPC community. We introduce new HPC-specific abstractions for message passing targeting distributed stencil computations. We demonstrate the sharing of common components across three distinct HPC stencil-DSL compilers: Devito, PSyclone, and the Open Earth Compiler, showing that our framework generates high-performance executables based upon a shared compiler ecosystem.

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arXiv2023

Stencil-HMLS: A multi-layered approach to the automatic optimisation of stencil codes on FPGA

The challenges associated with effectively programming FPGAs have been a major blocker in popularising reconfigurable architectures for HPC workloads. However new compiler technologies, such as MLIR, are providing new capabilities which potentially deliver the ability to extract domain specific information and drive automatic structuring of codes for FPGAs. In this paper we explore domain specific optimisations for stencils, a fundamental access pattern in scientific computing, to obtain high performance on FPGAs via automated code structuring. We propose Stencil-HMLS, a multi-layered approach to automatic optimisation of stencil codes and introduce the HLS dialect, which brings FPGA programming into the MLIR ecosystem. Using the PSyclone Fortran DSL, we demonstrate an improvement of 14-100$\times$ with respect to the next best performant state-of-the-art tool. Furthermore, our approach is 14 to 92 times more energy efficient than the next most energy efficient approach.

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arXiv2023

Fortran High-Level Synthesis: Reducing the barriers to accelerating HPC codes on FPGAs

In recent years the use of FPGAs to accelerate scientific applications has grown, with numerous applications demonstrating the benefit of FPGAs for high performance workloads. However, whilst High Level Synthesis (HLS) has significantly lowered the barrier to entry in programming FPGAs by enabling programmers to use C++, a major challenge is that most often these codes are not originally written in C++. Instead, Fortran is the lingua franca of scientific computing and-so it requires a complex and time consuming initial step to convert into C++ even before considering the FPGA. In this paper we describe work enabling Fortran for AMD Xilinx FPGAs by connecting the LLVM Flang front end to AMD Xilinx's LLVM back end. This enables programmers to use Fortran as a first-class language for programming FPGAs, and as we demonstrate enjoy all the tuning and optimisation opportunities that HLS C++ provides. Furthermore, we demonstrate that certain language features of Fortran make it especially beneficial for programming FPGAs compared to C++. The result of this work is a lowering of the barrier to entry in using FPGAs for scientific computing, enabling programmers to leverage their existing codebase and language of choice on the FPGA directly.

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arXiv2023

Task-based preemptive scheduling on FPGAs leveraging partial reconfiguration

FPGAs are an attractive type of accelerator for all-purpose HPC computing systems due to the possibility of deploying tailored hardware on demand. However, the common tools for programming and operating FPGAs are still complex to use, especially in scenarios where diverse types of tasks should be dynamically executed. In this work we present a programming abstraction with a simple interface that internally leverages High-Level Synthesis, Dynamic Partial Reconfiguration and synchronisation mechanisms to use an FPGA as a multi-tasking server with preemptive scheduling and priority queues. This leads to an improved use of the FPGA resources, allowing the execution of several different kernels concurrently and deploying the most urgent ones as fast as possible. The results of our experimental study show that our approach incurs only a 10% overhead in the worst case when using two reconfigurable regions, whilst providing a significant performance improvement of at least 24% over the traditional full reconfiguration approach.

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arXiv2022

Programming abstractions for preemptive scheduling in FPGAs using partial reconfiguration

FPGAs are an attractive type of accelerator for all-purpose HPC computing systems due to the possibility of deploying tailored hardware on demand. However, the common tools for programming and operating FPGAs are still complex to use, specially in scenarios where diverse types of tasks should be dynamically executed. In this work we present a programming abstraction with a simple interface that internally leverages High-Level Synthesis, Dynamic Partial Reconfiguration and synchronisation mechanisms to use an FPGA as a multi-tasking server with preemptive scheduling and priority queues. This leads to a better use of the FPGA resources, allowing the execution of several kernels at the same time and deploying the most urgent ones as fast as possible. The results of our experimental study show that our approach incurs only a 1.66% overhead when using only one Reconfigurable Region (RR), and 4.04% when using two RRs, whilst presenting a significant performance improvement over the traditional non-preemptive full reconfiguration approach.

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