Brice Goglin

Performance analysis of remote file system access over a high-speed local network

Summary form only given. We study the performance of remote file system access in a cluster environment. Our experimental lightweight system is called ORFA and aims at providing high performance for general purpose file access. Using a simple protocol allows us to get the best performance from the underlying communication subsystem. Our user-level implementation avoids several kernel constraints and thus provides better performance than NFS. Moreover, we explore several optimization techniques to reduce the server overhead, which usually is the bottleneck. Performance evaluation shows that data access may saturate the network link while the server remains scalable.

Optimizations of client's side communications in a distributed file system within a Myrinet cluster

High performance applications running on high-speed interconnects require both efficient communication between computing nodes and fast access to the storage system. Making the most of these networks to access remote files requires a good interaction between their highly specific software interface and the special requirements of distributed file systems. We show how non-buffered and buffered remote file access may be improved by modifying the network programming interface and firmware and by adding the required infrastructure in the operating system. Our modifications in Myrinet/GM show no performance penalty while the network usage in our ORFA (optimized remote file access) protocol is improved.

An Efficient Network API for in-Kernel Applications in Clusters

Running parallel applications on clusters with highspeed local networks requires fast communication between computing nodes but also low latency and high bandwidth file access. However, the application programming interfaces of high-speed local networks were designed for MPI communication and do not always meet the requirements of other applications like distributed file systems. In this paper, we explore several solutions to improve the use of high-speed network for in-kernel applications. Distributed file systems implemented on top of the GM interface of MYRINET are first examined to demonstrate how hard it is to get an efficient interaction between such applications and the network. Then, we propose solutions to simplify and improve this interaction and integrate them into the kernel interface of the new MYRINET driver, MX. Performance comparisons between MX and GM, and their usage in both a distributed file system and a zero-copy protocol show nice improvements. Moreover, we are able to improve the performance of the flexible kernel API we designed in MX that allows to remove some intermediate copy