scholarly journals Linux Low-Latency Tracing for Multicore Hard Real-Time Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Raphaël Beamonte ◽  
Michel R. Dagenais
Keyword(s):  
Real Time ◽  
Analysis Tool ◽  
Time Behavior ◽  
Real Time Systems ◽  
Real Time System ◽  
The Real ◽  
Real Time Analysis ◽  
Hard Real Time ◽  
Time Systems ◽  
The Impact

Real-time systems have always been difficult to monitor and debug because of the timing constraints which rule out any tool significantly impacting the system latency and performance. Tracing is often the most reliable tool available for studying real-time systems. The real-time behavior of Linux systems has improved recently and it is possible to have latencies in the low microsecond range. Therefore, tracers must ensure that their overhead is within that range and predictable and scales well to multiple cores. The LTTng 2.0 tools have been optimized for multicore performance, scalability, and flexibility. We used and extended the real-time verification tool rteval to study the impact of LTTng on the maximum latency on hard real-time applications. We introduced a new real-time analysis tool to establish the baseline of real-time system performance and then to measure the impact added by tracing the kernel and userspace (UST) with LTTng. We then identified latency problems and accordingly modified LTTng-UST and the procedure to isolate the shielded real-time cores from the RCU interprocess synchronization routines. This work resulted in extended tools to measure the real-time properties of multicore Linux systems, a characterization of the impact of LTTng kernel and UST tracing tools, and improvements to LTTng.

scholarly journals Performance of Dynamic Queue based Minimal Deadline First Scheduling Algorithm in Multicore System Under Real Time and NonReal Time Kernel Environment

2019 ◽  
Vol 8 (11) ◽  
pp. 3263-3268
Keyword(s):  
Operating System ◽  
Real Time ◽  
Low Cost ◽  
Scheduling Algorithm ◽  
Priority Queue ◽  
Real Time Systems ◽  
Real Time System ◽  
Core System ◽  
Hard Real Time ◽  
Time Systems

Some real-time systems that need to be associated with operating system services with a hard real-time system. Since these real-time systems that need to be extremely responsive to the outside world have no simple and low-cost operating system assistance. This paper deals with the application on a Linux-based operating system of the priority-based preemptive real-time scheduling algorithm that will suffice these firm applications in real-time. Typically, the algorithms regarded for these hard real-time systems are preemptive scheduling based on priorities. Based on the priority, by meeting the deadline, this algorithm can produce a feasible schedule for the dynamic tasks to be performed on the processor. It is feasible to schedule tasks on a processor as long as preemption is permitted and tasks do not compete for resources. In this scheduling algorithm, the task in the running queue that is waiting for the execution will be placed in the priority queue that is ready to execute in the available processor. This algorithm is deployed in the Linux kernel with the patch file and the kernel is built in the multi core system to execute an application

Formal Specification of a Wall-Climbing Robot Using Z – A Case Study of Small-Scale Embedded Hard Real-Time System

2012 ◽  
Author(s):  
Radziah Mohamad ◽  
Dyg. Norhayati Abg. Jawawi ◽  
Safaai Deris ◽  
Rosbi Mamat
Keyword(s):  
Real Time ◽  
Formal Methods ◽  
Software Reliability ◽  
Formal Specification ◽  
Small Scale ◽  
Real Time Systems ◽  
Time System ◽  
Real Time System ◽  
Hard Real Time ◽  
Time Systems

Aktiviti menguji sama ada sistem masa nyata memenuhi spesifikasi masa dan keserempakan adalah sangat penting. Salah satu bidang penyelidikan dalam bidang keboleh-percayaan perisian ialah teknik formal yang cuba untuk membuktikan kesahihan sesuatu atur cara dengan spesifikasinya. Oleh kerana masa dan keserampakan merupakan aspek yang penting dalam sistem masa nyata, keperluan untuk menggunakan teknik formal sebagai teknik untuk mengesahkan aspek masa dan keserempakan ini adalah amat tinggi. Kertas kerja ini mengkaji proses membina spesifikasi formal untuk sistem masa nyata berskala kecil dengan menggunakan teknik Z. Spesifikasi formal yang dibangunkan di dalam kertas kerja ini diharap dapat membantu proses penganalisisan fasa reka bentuk di awal proses pembangunan sistem. Kertas kerja ini juga diharap dapat menjadi rujukan kepada projek–projek teknik formal yang akan datang terutamanya projek yang berkaitan dengan sistem masa nyata berskala kecil. Kata kunci: Kebolehpercayaan perisian; spesifikasi formal; Z; masa nyata; sistem berskala kecil. The task of checking whether a real–time system satisfies its timing and concurrency specifications is extremely important. One major area of research addressing software reliability aspect is called formal method, which attempts to prove the correctness of programs with respect to system specifications. Since, timing and concurrency properties can very important in the operation of real–time systems, there is a need for applying formal methods to verify timing properties. This paper investigates the process of building a formal specification of a small-scale embedded hard real–time systems using Z. It is expected that the formal specification presented in this paper can provide assistance in analysing design trade–offs early in the development process. It is also expected that this paper can act as the foundation for any upcoming formal methods related project especially for small-scale real–time systems project. Key words: Software reliability; formal specification; Z; hard real-time; small-scale systems

A Parallelization Approach for Hard Real-Time Systems and Its Application on Two Industrial Programs

2016 ◽  
Vol 44 (6) ◽  
pp. 1296-1336 ◽  
Author(s):  
Martin Frieb ◽  
Ralf Jahr ◽  
Haluk Ozaktas ◽  
Andreas Hugl ◽  
Hans Regler ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Systems ◽  
Hard Real Time ◽  
Time Systems
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