Our aim is to investigate the suitability of hardware multithreading for real-time event handling in combination with appropriate real-time scheduling techniques. We designed and evaluated a multithreaded microcontrol...
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Our aim is to investigate the suitability of hardware multithreading for real-time event handling in combination with appropriate real-time scheduling techniques. We designed and evaluated a multithreaded microcontroller based on a Java processor core. Java threads are used as Interrupt Service Threads (ISTs) instead of the Interrupt Service Routines (ISRs) of conventional processors. Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. A so-called priority manager implements several realtime scheduling algorithms in hardware. We show the feasibility of a hardware real-time scheduler integrated deeply into the processor pipeline with a VHDL design and its synthesis. Evaluations with a software simulator and real-time applications as benchmarks show that hardware multithreading reaches a 1.2-1.4 performance increase for hard real-time applications (multithreading without latency utilization) and a 2.0-2.6 speedup by latency utilization for programs without hard real-time requirements. With respect to real-time scheduling on a multithreaded microcontroller, the Least Laxity First (LLF) scheme outperforms the Fixed Priority Preemptive (FPP), Earliest Deadline First (EDF), and Guaranteed Percentage (GP) schemes, but suffers from the highest implementation costs. (C) 2002 Elsevier Science B.V. All rights reserved.
We propose a multithreaded Java microcontroller--called Komodo microcontroller--with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Re...
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ISBN:
(纸本)9780769504254
We propose a multithreaded Java microcontroller--called Komodo microcontroller--with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as interrupt service threads (ISTs) instead of interrupt service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
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