AuthorsC. H. Lunde, H. Espeland, H. K. Stensland and P. Halvorsen
EditorsS. Zhong
TitleImproving File Tree Traversal Performance by Scheduling I/O Operations in User Space
AfilliationCommunication Systems, Communication Systems
Publication TypeProceedings, refereed
Year of Publication2009
Conference NameProceedings of the 28th IEEE International Performance Computing and Communications Conference (IPCCC)
ISBN Number978-1-4244-5736-6

Current in-kernel disk schedulers provide efficient means to optimize the order (and minimize disk seeks) of issued, in-queue I/O requests. However, they fail to optimize sequential multi-file operations, like traversing a large file tree, because only requests from one file are available in the scheduling queue at a time. We have therefore investigated a user-level, I/O request sorting approach to reduce inter-file disk arm movements. This is achieved by allowing applications to utilize the placement of inodes and disk blocks to make a one sweep schedule for all file I/Os requested by a process, i.e., data placement information is read first before issuing the low-level I/O requests to the storage system. Our experiments with a modified version of tar show reduced disk arm movements and large performance improvements.

Citation KeySimula.ND.407