Memory Resource Management for Real-Time Systems

Marchand, A.; Balbastre, Patricia; Ripoll, Ismael; Masmano, Miguel; Crespo, Alfons

doi:10.1109/ecrts.2007.18

Cited by 16 publications

(15 citation statements)

References 20 publications

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“…Real-time memory management techniques in the context of dynamic memory allocation have also been studied in [11] [17][12] [13]. They aim to meet changing memory demands of user-level applications under real-time timing constraints.…”

Section: A Related Workmentioning

confidence: 99%

“…This makes the primary performance effect of the application's memory access be contained within its reservation set, thereby providing temporal isolation to each application. Moreover, as memory reservation provides an abstraction for a logically partitioned physical memory area, other real-time memory techniques such as page replacement [7], prefetching [2], and dynamic memory allocation [11] can run on top of memory reservation, and each memory reservation set could be allowed to choose the best-suited memory technique and parameters for its associated applications.…”

Section: Introductionmentioning

confidence: 99%

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Shared-Page Management for Improving the Temporal Isolation of Memory Reservations in Resource Kernels

Kim

Rajkumar

2012

2012 IEEE International Conference on Embedded and Real-Time Computing Systems and Applications

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Memory reservation provides real-time applications with guaranteed memory access to a specified amount of physical memory. However, previous work on memory reservation primarily focused on private pages, and did not pay attention to shared pages, which are widely used in current operating systems. With previous schemes, a real-time application may experience unexpected timing delays from other applications through shared pages that are shared by another process, even though the application has enough free pages in its reservation. In this paper, we describe problems with shared pages in real-time applications, and propose a shared-page management mechanism to enhance the temporal isolation of memory reservations in resource kernels that use resource reservation. The proposed mechanism consists of two techniques, Shared-Page Conservation (SPC) and Shared-Page Eviction Lock (SPEL), each of which prevents timing penalties caused by the seemingly arbitrary eviction of shared pages. The mechanism can manage shared data for inter-process communication and shared libraries, as well as pages shared by the kernel's copy-on-write technique and file caches. We have implemented and evaluated our schemes on the Linux/RK platform, but it can be applied to other operating systems with paged virtual memory.

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Section: A Related Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Shared-Page Management for Improving the Temporal Isolation of Memory Reservations in Resource Kernels

Kim

Rajkumar

2012

2012 IEEE International Conference on Embedded and Real-Time Computing Systems and Applications

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“…A half-fit allocator [7] with constant execution time was proposed but suffers from high fragmentation [1]. A half-fit allocator [7] with constant execution time was proposed but suffers from high fragmentation [1].…”

Section: Related Workmentioning

confidence: 99%

“…There are three important requirements for a dynamic memory allocator to be used for real-time systems [1], [2]: bounded worst-case execution time, fast average execution time, and minimal fragmentation. In this paper, we focus on minimizing fragmentation while the other requirements are still satisfied.…”

Section: Introductionmentioning

confidence: 99%

Improving Memory Efficiency of Dynamic Memory Allocators for Real-Time Embedded Systems

Lee¹,

Yi²

2011

ETRI J

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Dynamic memory allocators for real‐time embedded systems need to fulfill three fundamental requirements: bounded worst‐case execution time, fast average execution time, and minimal fragmentation. Since embedded systems generally run continuously during their whole lifetime, fragmentation is one of the most important factors in designing the memory allocator. This paper focuses on minimizing fragmentation while other requirements are still satisfied. To minimize fragmentation, a part of a memory region is segregated by the proposed budgeting method that exploits the memory profile of the given application. The budgeting method can be applied for any existing memory allocators. Experimental results show that the memory efficiency of allocators can be improved by up to 18.85% by using the budgeting method. Its worst‐case execution time is analyzed to be bounded.

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“…(The operator can use the provided utility to modify these data structures at run time, e.g., when a new VM is created or an existing VM is destroyed.) However, we note that there is a rich literature on working-set estimation [9,31] and on memory management for real-time tasks [12,20], which can be adapted for use with cache partitions.…”

Section: Hypervisor-level Partition Allocationmentioning

confidence: 99%

vCAT: Dynamic Cache Management Using CAT Virtualization

Thi²,

Phan

et al. 2017

2017 IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS)

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This paper presents vCAT, a novel design for dynamic shared cache management on multicore virtualization platforms based on Intel's Cache Allocation Technology (CAT). Our design achieves strong isolation at both task and VM levels through cache partition virtualization, which works in a similar way as memory virtualization, but has challenges that are unique to cache and CAT. To demonstrate the feasibility and benefits of our design, we provide a prototype implementation of vCAT, and we present an extensive set of microbenchmarks and performance evaluation results on the PARSEC benchmarks and synthetic workloads, for both static and dynamic allocations. The evaluation results show that (i) vCAT can be implemented with minimal overhead, (ii) it can be used to mitigate shared cache interference, which could have caused task WCET increased by up to 7.2 x, (iii) static management in vCAT can increase system utilization by up to 7 x compared to a system without cache management; and (iv) dynamic management substantially outperforms static management in terms of schedulable utilization (increase by up to 3 x in our multi-mode example use case). Abstract-This paper presents vCAT, a novel design for dynamic shared cache management on multicore virtualization platforms based on Intel's Cache Allocation Technology (CAT). Our design achieves strong isolation at both task and VM levels through cache partition virtualization, which works in a similar way as memory virtualization, but has challenges that are unique to cache and CAT. To demonstrate the feasibility and benefits of our design, we provide a prototype implementation of vCAT, and we present an extensive set of microbenchmarks and performance evaluation results on the PARSEC benchmarks and synthetic workloads, for both static and dynamic allocations. The evaluation results show that (i) vCAT can be implemented with minimal overhead, (ii) it can be used to mitigate shared cache interference, which could have caused task WCET increased by up to 7.2×, (iii) static management in vCAT can increase system utilization by up to 7× compared to a system without cache management; and (iv) dynamic management substantially outperforms static management in terms of schedulable utilization (increase by up to 3× in our multi-mode example use case). Disciplines Computer Engineering | Computer Sciences

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Memory Resource Management for Real-Time Systems

Cited by 16 publications

References 20 publications

Shared-Page Management for Improving the Temporal Isolation of Memory Reservations in Resource Kernels

Shared-Page Management for Improving the Temporal Isolation of Memory Reservations in Resource Kernels

Improving Memory Efficiency of Dynamic Memory Allocators for Real-Time Embedded Systems

vCAT: Dynamic Cache Management Using CAT Virtualization

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