Emmanuelle Saillard (Storm)

Hi everyone,

Be joyful! A new Storm Talk is coming our way!

This time, we will have the honor to learn about error detection in MPI-RMA programs from none other than Emmanuelle Saillard.

Join us on October 27 at 2 pm in George Boole 2 or online, or regret missing it out.

Speaker

Emmanuelle Saillard (Storm)

When

Thursday, October 27, 2022 at 2 pm.

Where

room George Boole 2

Title

Static Local Concurrency Errors Detection in MPI-RMA Programs

Abstract

Communications are a critical part of HPC simulations, and one of the main focuses of application developers when scaling on supercomputers. While classical message passing (also called two-sided communications) is the dominant communication paradigm, one-sided communications are often praised to be efficient to overlap communications with computations, but challenging to program. Their usage is then generally abstracted through languages and memory abstractions to ease programming (e.g. PGAS). Therefore, little work has been done to help programmers use intermediate runtime layers, such as MPI-RMA, that are often reserved for expert programmers. Indeed, programming with MPI-RMA presents several challenges that require handling the asynchronous nature of one-sided communications to ensure the proper semantics of the program while ensuring its memory consistency. To help programmers detect memory errors such as race conditions as early as possible, this talk proposes a new static analysis of MPI-RMA codes that shows to the programmer the errors that can be detected at compile time. The detection is based on a novel local concurrency errors detection algorithm that tracks accesses through BFS searches on the Control Flow Graphs of a program. We show on several tests and an MPI-RMA variant of the GUPS benchmark that the static analysis allows us to detect such errors on user code