CRAFT: A library for easier application-level Checkpoint/Restart and Automatic Fault Tolerance

TL;DR

CRAFT is a C++ library that simplifies implementing application-level checkpointing and fault tolerance in HPC, reducing overhead and effort for fault recovery.

Contribution

It introduces an extendable, easy-to-use library that combines checkpointing and dynamic process recovery for high-performance computing applications.

Findings

Reduces implementation effort for application-level checkpointing

Supports asynchronous checkpointing and node-level checkpointing

Thoroughly analyzed overheads with multiple benchmarks

Abstract

In order to efficiently use the future generations of supercomputers, fault tolerance and power consumption are two of the prime challenges anticipated by the High Performance Computing (HPC) community. Checkpoint/Restart (CR) has been and still is the most widely used technique to deal with hard failures. Application-level CR is the most effective CR technique in terms of overhead efficiency but it takes a lot of implementation effort. This work presents the implementation of our C++ based library CRAFT (Checkpoint-Restart and Automatic Fault Tolerance), which serves two purposes. First, it provides an extendable library that significantly eases the implementation of application-level checkpointing. The most basic and frequently used checkpoint data types are already part of CRAFT and can be directly used out of the box. The library can be easily extended to add more data types. As means of overhead reduction, the library offers a build-in asynchronous checkpointing mechanism and also supports the Scalable Checkpoint/Restart (SCR) library for node level checkpointing. Second, CRAFT provides an easier interface for User-Level Failure Mitigation (ULFM) based dynamic process recovery, which significantly reduces the complexity and effort of failure detection and communication recovery mechanism. By utilizing both functionalities together, applications can write application-level checkpoints and recover dynamically from process failures with very limited programming effort. This work presents the design and use of our library in detail. The associated overheads are thoroughly analyzed using several benchmarks.