Sergio Ruocco

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This paper investigates the validity of common approaches to power management based on dynamic voltage scaling (DVS). Using instrumented hardware and appropriate operating-system support, we account separately for energy consumed by the processor and the memory system. We find that memory often contributes significantly to overall power consumption, which(More)
Search-coil magnetometers are of common use in space physics thanks to their simplicity, robustness and ability to measure weak magnetic fields: their sensitivity can reach a few tens of fT/¿Hz in the range 10-100 kHz. The frequency band is grossly determined by the resonance of the coil. Simply adding a second coil does not efficiently extend the frequency(More)
This paper investigates the impact of voltage scaling on energy and performance of STT-MRAM arrays under write access, which is well known to be energy critical. Simple analytical models of energy and delay are introduced to gain an insight into the energy-performance tradeoff at low voltages, and minimum-energy operation. The minimum-energy point is found(More)
L4-embedded is a microkernel successfully deployed in mobile devices with soft real-time requirements that now faces the challenges of tightly integrated systems, where user interface, multimedia, OS, wireless protocols and even software-defined radios must run on a single CPU. This paper discusses the various aspects of real-time programming on(More)
The L4 microkernel, like many first and second generation microkernels, was designed to maximise best-effort performance. One component of its functionality critical to overall system performance is its interprocess communication primitive. L4 uses two techniques to minimise communication costs: direct process switching and lazy queue management. These(More)
  • Sergio Ruocco
  • 2006 27th IEEE International Real-Time Systems…
  • 2006
Real-time systems must adapt their behaviour when the timing assumptions they are based on change at run time. A viable approach leading to effective adaptations consists of exploiting application-specific knowledge, but limitations of ordinary schedulers constrain its applicability. In this paper this problem is tackled using a reflective scheduler, which(More)
Current design approaches to time-sensitive systems do not provide a coherent architectural framework for "non-functional" time-related requirements. The paper proposes Temporal Reflection as the ability of a system to self-represent, observe and adapt its own temporal behaviour through suitable architectural abstractions. The paper provides the rationale(More)
This paper investigates the impact of voltage scaling on the energy and the performance of STT-RAM bitcells during write operation. Analytical models of energy scaling and performance degradation are derived to gain an insight into the energy-performance tradeoff at low voltages. Minimum-energy operation is explored through optimization of the supply(More)