Mixed Time-Criticality Process Interferences Characterization on a Multicore Linux System

Abstract

The increasing interest in the integration of Mixed-Criticality Systems (MCS) in Commercial-Off-The-Shelf (COTS) platforms leads to an increasing number of challenges. The possibility of sharing computing resources among applications with different time criticalities is a key goal for COTS systems, but still hard to achieve. Classical approaches in real-time systems are not feasible when platform and operating system may introduce unpredictability in the task execution. Moreover, if the system must also meet non-functional requirements (e.g., thermal and power management), dynamic approaches of computing resources allocation are more effective than static ones. Unfortunately, this contributes to increasing the complexity of the scenario. In MCS, the overheads and the unpredictability caused by sharing resources like cache memories have been well studied. However, in some cases we could also consider the operating system itself as a potential source of unexpected and unpredictable latencies, if several running tasks perform system calls. This work aims at proposing a model for the intra-core and inter-core interferences and the analysis of the OS-induced latencies in a Linux real-time system, both essential for the creation of smart and effective run-time resource management policies.

Do Impacto das Syscalls Linux em Tarefas de Tempo Real

“…Em [Reghenzani et al 2017],é proposto um modelo para interferências intra e inter kernel eé realizada uma análise quantitativa da sobrecarga induzida pelo SO. Nos experimentos, os autores identificaram que uma tarefa comum pode aumentar em mais de 50% o pior tempo e o tempo médio de execução de uma tarefa de tempo real crítica apenas pelas syscalls Linux que ela realiza.…”

Plataforma Modular Reconfigurable como Nueva Filosofía para el Desarrollo de Electrónica Vehicular Actualizable

“…Un sistema de criticidad mixta (MSC) es aquél que tiene dos o más niveles distintos de criticidad (por ejemplo, crítico para la seguridad, para la misión, y de baja criticidad). La criticidad es una designación del nivel de seguridad contra fallos (Reghenzani et al, 2017).…”

“…Mas tarde se trabaja en la escalabilidad de sistemas multinúcleo basado en FPGA en Kliem y Voigt (2014). Han et al (2017) analizan las posibilidades de compartir recursos en MSC multinúcleo basándose en la limitación de la carga de trabajo y el bloqueo de la sobrecarga y Reghenzani et al (2017) analizan la caracterización de interferencias en MSC bajo sistemas multinúcleo Linux. Deutschbein et al (2017) analizan el funcionamiento de las tareas en modo ciclo en sistemas críticos para la seguridad y multinúcleo y Li et al (2017) proponen un sistema de programación federada de criticidad mixta para tareas paralelas en tiempo real.…”

“…La ejecución en la SBC es multinúcleo, lo que no es trivial (Han et al, 2017). Bajo condiciones de un sistema operativo no determinista convencional, aparecen problemas en la ejecución en tiempo real de tareas críticas (Reghenzani et al, 2017). Garantizar una latencia constante y pequeña (en el orden de pocos milisegundos) de forma que el comportamiento sea de tiempo real es una necesidad muy importante de cara a un buen comportamiento del regulador y a garantizar la seguridad del sistema.…”

Parameter Analysis of Interfering Applications in Multi-Core Environment for Throughput Enhancement

“…The purpose of the benchmark to quantify how SPLASH-2 benchmarks behavior changes considering the said memory types. For finding the interference effects in real-time systems, the worst-case execution time is considered an effective approach [26]. The worst-case execution time helps on finding the "severe interference situation" in real-time Multi-core systems, which determines the peak value of slow down an application would feel on the conflicting environments.…”