Multi-core technology is bringing parallel processing capabilities
from servers to laptops and even handheld devices. At the same time,
platform support for system virtualization is making it easier to
consolidate server and client resources, when and as needed by
applications. This consolidation is achieved by dynamically mapping
the virtual machines on which applications run to underlying
physical machines and their processing cores. Low cost processor and
I/O virtualization methods efficiently scaled to different numbers of
processing cores and I/O devices are key enablers of such consolidation.
This dissertation develops and evaluates new methods for scaling
virtualization functionality to multi-core and future many-core systems.
Specifically, it re-architects virtualization functionality to improve
scalability and better exploit multi-core system resources. Results
from this work include a self-virtualized I/O abstraction, which
virtualizes I/O so as to flexibly use different platforms' processing
and I/O resources. Flexibility affords improved performance and resource
usage and most importantly, better scalability than that offered by
current I/O virtualization solutions. Further, by describing system virtualization as a
service provided to virtual machines and the underlying computing platform,
this service can be enhanced to provide new and innovative functionality.
For example, a virtual device may provide obfuscated data to guest operating
systems to maintain data privacy; it could mask differences in device
APIs or properties to deal with heterogeneous underlying resources; or it
could control access to data based on the ``trust' properties of the
guest VM.
This thesis demonstrates that extended virtualization services are
superior to existing operating system or user-level implementations
of such functionality, for multiple reasons. First, this solution
technique makes more efficient use of key performance-limiting resource in
multi-core systems, which are memory and I/O bandwidth. Second, this
solution technique better exploits the parallelism inherent in multi-core
architectures and exhibits good scalability properties, in
part because at the hypervisor level, there is greater control in precisely
which and how resources are used to realize extended virtualization services.
Improved control over resource usage makes it possible to provide
value-added functionalities for both guest VMs and the platform.
Specific instances of virtualization services described in this thesis are the
network virtualization service that exploits heterogeneous processing cores,
a storage virtualization service that provides location transparent access
to block devices by extending
the functionality provided by network virtualization service, a multimedia
virtualization service that allows efficient media device sharing based on semantic
information, and an object-based storage service with enhanced access
control.Ph.D.Committee Chair: Schwan, Karsten; Committee Member: Ahamad, Mustaq; Committee Member: Fujimoto, Richard; Committee Member: Gavrilovska, Ada; Committee Member: Owen, Henry; Committee Member: Xenidis, Jim
