DTA

Digital Theses Archive

 

Tesi etd-01192024-210812

Type of thesis
Dottorato
Author
ZINI, MATTEO
URN
etd-01192024-210812
Title
Analysis and Mitigation of Memory Contention in Real-Time Embedded Systems
Scientific disciplinary sector
ING-INF/05
Course
Istituto di Tecnologie della Comunicazione, dell'Informazione e della Percezione - PHD IN EMERGING DIGITAL TECHNOLOGIES
Committee
relatore Prof. BUTTAZZO, GIORGIO CARLO
Presidente Prof. ANDREA SARACINO
Membro Prof. GIOVANNI STEA
Keywords
  • memory
  • DRAM
  • memory contention
  • interference
  • QoS
  • QoS-400
  • MPAM
  • arm
  • WCET
  • I/O
  • virtualization
  • real-time systems
  • embedded systems
Exam session start date
03/06/2024;
Availability
parziale
Abstract
The thesis deals with the effect of memory interference on the WCET of tasks, its possible effects, and how hardware-based technologies can help to mitigate them.<br>The discussion is divided into fourparts: the first deals with the memory interference generated by I/O devices and how hardware-based memory-bandwidth regulators can help to mitigate its effects on both CPU cores and other devices.<br>The second part focuses on memory interference generated by CPU cores and the possibility of utilizing the ARMv8 MPAM extension in order to reduce it. The study begins with a deep analysis of the specifications that allow the creation of a real-time model of MPAM&#39;s mechanisms. These are exploited for the design of an optimization problem that can be used to compute the worst-case memory interference that can be guaranteed by MPAM&#39;s mechanisms.<br>The third part presents an I/O virtualization framework supporting memory bandwidth regulation on the traffic produced by I/O devices.<br>The fouth part deals instead with the possible effects of WCET overruns caused by interference. In particular, an analysis-based technique is developed in order to compute the minimum amount of extra interference needed to have a non-linear jump in the response-time bound of a task (computed through the response-time analysis). An optimization problem is finally built to exemplify possible real scenarios that could lead to such an increase in interference.
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