摘要：
This paper describes extensions to the Linux Trace Toolkit next generation (LTTng), to trace the Xen hypervisor for efficiently tracing complete systems. LTTng is a low impact, modular, extensible, operating system tracer, while Xen is an hypervisor based on paravirtualization. Typically, one or several instances of Linux will run on top of the Xen hypervisor. The extended LTTng is able to trace all Linux instances and the hypervisor layer to give a global view of the system.
An automated benchmark was created to measure the overhead imposed by tracing and Xen paravirtualization. It compares the performance of systems, with and without virtualization and tracing. The results obtained with different tests, using this procedure, are presented and show a negligible impact caused by tracing and a reasonable overhead caused by paravirtualization. Nonetheless, for some I/O intensive applications, the overhead imposed by paravirtualization is less negligible.
