Memory Data Access Timing Control for Real-Time Virtual Machines
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Solution Overview
Problem
Conventional techniques face challenges in controlling data access to memory while considering real-time processes executed by a host processor, particularly in virtual machine environments.
Innovation Solution
A controller is implemented with a data access unit, reception unit control, and time management unit to manage and control data access based on virtual machine and task scheduling information, ensuring that real-time processes are not hindered by memory access during their execution periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data access to memory is allowed during virtual machine execution, then productivity and resource utilization are improved, but real-time process execution reliability deteriorates due to unpredictable memory access delays
Solution Approach 1:
The memory access control is segmented by virtual machine types: real-time virtual machines are granted restricted access during their execution periods to ensure deterministic timing, while non-real-time virtual machines are allowed access during idle periods. This segmentation resolves the contradiction by separating memory access rights based on real-time requirements.
Solution Approach 2:
The memory access control dynamically adjusts based on the executing virtual machine's type and current execution period. The control unit monitors which virtual machine is executing and modifies memory access permissions in real-time, allowing flexible resource allocation while maintaining real-time guarantees when needed.
2Reliability
If memory access control is implemented for real-time processes, then real-time execution reliability is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
A control unit is introduced as an intermediary between the virtual machine execution and memory access. This control unit receives execution period information, determines the executing virtual machine type, and generates appropriate memory access control signals. The intermediary approach manages complexity by centralizing control logic in a dedicated component rather than distributing it throughout the system.
Solution Approach 2:
The system uses self-service by having the control unit automatically determine virtual machine types and generate control signals based on execution period information without requiring external intervention. The control unit queries the virtual machine execution information and autonomously adjusts memory access permissions, reducing the need for complex external control mechanisms.
3Reliability
If memory access is restricted during real-time virtual machine execution, then real-time process reliability is improved, but productivity decreases due to reduced memory access availability
Solution Approach 1:
Memory access control operates periodically based on virtual machine execution periods. During real-time virtual machine execution periods, memory access is restricted to ensure reliability. During non-real-time virtual machine execution periods, memory access is permitted to maintain productivity. This periodic switching resolves the contradiction by allocating memory access rights in time slices matched to virtual machine execution patterns.
Data Source
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AI summary
According to an embodiment, a processing apparatus (100) includes a data access unit (406), a reception unit (403), and a control unit (404). The data access unit (406) is configured to execute data access that is at least one of data writing to a memory (1) and data reading from the memory (1). The reception unit (403) is configured to receive access control information for controlling timing of the data access to be executed by the data access unit (406). The control unit (404) is configured to control the timing of the data access based on the access control information received by the reception unit (403).