Lazy Read: Asynchronous Execution of Synchronous File I/O

In the realm of High-Performance Computing (HPC), the disparity between I/O and processing capabilities can hinder application performance. One source of this I/O gap is the latency of the devices, especially in case of distributed filesystems (DFS). Prior solutions to minimize such negative effects (e.g. using asynchronous operations or separate I/O-Threads), have to be considered when designing an application. This work aims to execute these operations asynchronously for existing applications without necessitating modifications or even recompilation. To attain this objective, we introduce the Lazy Read approach, which alters how the operating system handles read requests. This modification enables the application to start multiple reads or do CPU work in parallel instead of waiting for completion of the read operation. For evaluation, we implemented the Lazy Read approach in the Linux kernel. We then showed that the approach adds overhead, however, multiple read operations can be executed in parallel. In our specific evaluation the maximum possible speedup was achieved, reducing the execution time by up to 50%.