Paravirtualization for Hpc Systems * Ucsb Computer Science Technical Report Number 2006-10

Virtualization has become increasingly popular for enabling full system isolation, load balancing, and hardware multiplexing. This wide-spread use is the result of novel techniques such as paravirtualization that make virtualization systems practical and efficient. Paravirtualizing systems export an interface that is slightly different from the underlying hardware but that significantly streamlines and simplifies the virtualization process. In this work, we investigate the efficacy of using paravirtualizing software for performance-critical HPC kernels and applications. Such systems are not currently employed in HPC environments due to their perceived overhead. However, virtualization systems offer tremendous potential for benefitting HPC systems by facilitating application isolation, portability, operating system customization, and program migration. We present a comprehensive performance evaluation of Xen, a low-overhead, Linux-based, virtual machine monitor (VMM), for paravirtualization of HPC cluster systems at Lawrence Livermore National Lab (LLNL). We consider four categories of micro-benchmarks from the HPC Challenge (HPCC) and LLNL ASCI Purple suites to evaluate a wide range of subsystem-specific behaviors. In addition, we employ macro-benchmarks and HPC application to evaluate overall performance in a real setting. We also employ statistically sound methods to compare the performance of a paravirtualized kernel against three popular Linux operating systems: RedHat Enterprise 4 (RHEL4) for build versions 2.6.9 and 2.6.12 and the LLNL CHAOS kernel, a specialized version of RHEL4. Our results indicate that Xen is This work is sponsored in part by grant from the National Science Foundation (ST-HEC-0444412). very efficient and practical for HPC systems.