Niels Penneman

Niels Penneman

Former Member

niels.penneman@elis.ugent.be
+32 9 264 98 57 (phone)
+32 9 264 35 94 (fax)

System Software Lab
Computing Systems Lab (CSL)
Electronics and Information Systems (ELIS) department
Ghent University
Sint Pietersnieuwstraat 41
9000 Ghent
Belgium


 

Research Project


Consider a future smartphone that combines software-defined radio (SDR) with advanced multimedia features. Control tasks and simple computational tasks are executed on some generic cores, while more compute-intensive tasks run on accelerators, e.g. for baseband processing and video coding. The latter is a soft real-time (soft RT) application, with a refresh rate of 25 Hz and varying bandwidth requirements, because of variations of the complexity in video streams. This application can share the compute cores and accelerators with other applications. At the same time, it has to be completely isolated from them because of digital rights management protection measures. In fact, every multimedia content provider wants to set up their own virtual appliance on the smartphone, which can be developed separately. Furthermore, the SDR modem software stack communicates with different types of networks, partially reusing the same compute cores and accelerators. Since network operators want to prevent users from tampering with their network, the modem software stack also needs to reside in its own, isolated environment. This software stack is a hard RT application, with varying bandwidth and RT requirements because of the diversity of the supported communication standards. The standard to be used is determined dynamically, based on the available channels and their quality, which can vary with every footstep of the user. Next to all these, smartphones also comprise best-effort applications; e.g. address books, calendars, etc. Two trends merge: the extensive combination of hard RT, soft RT and best effort applications within the same device, and the consolidation of hardware, i.e. reducing the number of processors by allowing multiple applications to share the same hardware. Because applications can no longer be isolated from each other, and instead run consolidated on shared hardware, isolation is enforced through system-level virtualization. In other words, multiple applications with their own RTOS may run concurrently in independent virtual machines (VMs). The OSs inside the VMs manage virtual system resources, as assigned to them by the hypervisor. The hypervisor thus manages the physical hardware resources and the RTOSs interact solely with virtual resources. Existing research on RTOSs focuses on systems with a fixed set of system resources. When using multiple, isolated RT schedulers in systems such as the smartphone mentioned earlier, where system resources are assigned by a hypervisor, this assumption no longer holds. The core problem tackled in this project is that, in order to optimally use hardware resources, the hypervisor should adaptively assign them to the different VMs, similar to the way adaptive RT schedulers work within non-virtualized OSs. Existing virtualization solutions for RT systems use paravirtualization techniques to reduce software overhead and capture RT behavior. However, these solutions do not support fully adaptive resource assignment, and the use of paravirtualization limits the extent to which virtual appliances can be developed independently. The main goal of my research project is the development of techniques enabling RT application designers to use system-level virtualization. More specifically, they will be able to benefit from adaptive resource management on the hypervisor level.





Contact person for Projects:

Title Type Project year
Debuggen van gevirtualiseerde systemen Master thesis 2013
Virtualisatie voor smartphones en tablets van de toekomst Master thesis 2013

Publications to Appear



Publications


Journal papers

  1. Niels Penneman, Danielius Kudinskas, Alasdair Rawsthorne, Bjorn De Sutter and Koen De Bosschere Formal virtualization requirements for the ARM architecture JOURNAL OF SYSTEMS ARCHITECTURE, pp. 12 (2013)

Conference publications

  1. Niels Penneman, Luc Perneel, Martin Timmerman and Bjorn De Sutter An FPGA-based real-time event sampler LECTURE NOTES IN COMPUTER SCIENCE, Vol. 5992, pp. 364-371 (2010)