Interference of Hard IRQs and Soft IRQs in Real-Time Priority Tasks on Linux

• Andreu Carminati UFSC
• Rômulo Silva de Oliveira UFSC

Abstract

The operating system Linux is nowadays an attractive alternative for a great spectrum of applications. Mainline Linux can be used for soft real-time. There are Linux variations (patch’s and extensions) to further improve its capability of supporting soft real-time applications. However, some companies that use Linux embedded in products that need soft real-time prefer to use mainline Linux, since its maintenance and evolution is more guaranteed than those based on alternative patches. This paper is specifically about the interference generated by the executions of Softirqs and Hard irqs on tasks with maximum real-time priority in mainline Linux. Softirqs are those activities that happen inside of the kernel due to a hardware interrupt, but that are not executed immediately by the interrupt handler. The goal of this work is evaluate the impact of the Softirq and Hard irq activities on tasks with real-time priority.

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