USENIX Update

Presented at the 9th USENIX Symposium on Operating Systems Design and Implementation (OSDI '10) held in Vancouver, BC, Canada, October 4-6, 2010. Paper authors: Amittai Aviram, Shu-Chun Weng, Sen Hu, and Bryan Ford, Yale University Abstract: Deterministic execution offers many benefits for debugging, fault tolerance, and security. Current methods of executing parallel programs deterministically, however, often incur high costs, allow misbehaved software to defeat repeatability, and transform time-dependent races into input- or path-dependent races without eliminating them. We introduce a new parallel programming model addressing these issues, and use Determinator, a proof-of-concept OS, to demonstrate the model's practicality. Determinator's microkernel API provides only "shared-nothing" address spaces and deterministic interprocess communication primitives to make execution of all unprivileged code—well-behaved or not—precisely repeatable. Atop this microkernel, Determinator's user-level runtime adapts optimistic replication techniques to offer a private workspace model for both thread-level and process-level parallel programing. This model avoids the introduction of read/write data races, and converts write/write races into reliably-detected conflicts. Coarse-grained parallel benchmarks perform and scale comparably to nondeterministic systems, on both multicore PCs and across nodes in a distributed cluster.

Presented at the 9th USENIX Symposium on Operating Systems Design and Implementation (OSDI '10) held in Vancouver, BC, Canada, October 4-6, 2010. Paper authors: Muli Ben-Yehuda, IBM Research—Haifa; Michael D. Day, IBM Linux Technology Center; Zvi Dubitzky, Michael Factor, Nadav Har'El, and Abel Gordon, IBM Research—Haifa; Anthony Liguori, IBM Linux Technology Center; Orit Wasserman and Ben-Ami Yassour, IBM Research—Haifa Abstract: In classical machine virtualization, a hypervisor runs multiple operating systems simultaneously, each on its own virtual machine. In nested virtualization, a hypervisor can run multiple other hypervisors with their associated virtual machines. As operating systems gain hypervisor functionality—Microsoft Windows 7 already runs Windows XP in a virtual machine—nested virtualization will become necessary in hypervisors that wish to host them. We present the design, implementation, analysis, and evaluation of high-performance nested virtualization on Intel x86-based systems. The Turtles project, which is part of the Linux/KVM hypervisor, runs multiple unmodified hypervisors (e.g., KVM and VMware) and operating systems (e.g., Linux and Windows). Despite the lack of architectural support for nested virtualization in the x86 architecture, it can achieve performance that is within 6-8% of single-level (non-nested) virtualization for common workloads, through multi-dimensional paging for MMU virtualization and multi-level device assignment for I/O virtualization.

The 9th USENIX Symposium on Operating Systems Design and Implementation (OSDI ’10) seeks to present innovative, exciting research in computer systems. OSDI brings together professionals from academic and
industrial backgrounds in what has become a premier forum for discussing the design, implementation, and implications of systems software.

More information and submission guidelines can be found here.

Submissions Deadline: May 7, 2010

OSDI ’10 will take place October 4-6, 2010, in Vancouver, BC, Canada.
Sponsored by USENIX in cooperation with ACM SIGOPS.