Implementation and evaluation of global and partitioned scheduling in a real-time OS

Gracioli, Giovani; Fröhlich, Antônio Augusto; Pellizzoni, Rodolfo; Fischmeister, Sebastian

doi:10.1007/s11241-013-9183-3

Cited by 43 publications

(29 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…EPOS hard real-time scheduler [18] ensures that the idle thread is only scheduled when there is no other thread to run. The idle thread is, therefore, the entity in charge of keeping the system configuration tuned with the reconfiguration policy specified by the user.…”

Section: B Api Reconfigurationmentioning

confidence: 99%

X-Ware: mutant computing substrates

Reis

Fröhlich

Wanner

2015

2015 International Symposium on Rapid System Prototyping (RSP)

View full text Add to dashboard Cite

In this paper we introduce X-Ware, a framework for computing whereby components used by an application can take different forms and characteristics across the lifetime of the system in order to adjust to dynamic application requirements. In particular, we explore two aspects of system mutability: dynamic choice of implementations for certain system components (e.g., leading to different trade-offs between quality and resource usage); and the change in non-functional characteristics of these components (e.g., speed and energy consumption) due to process and environmental variations. We demonstrate X-Ware with a library of mathematical APIs that can help components save up to 93% in energy and 94% in execution time by tolerating a small degradation in quality.

show abstract

Section: B Api Reconfigurationmentioning

confidence: 99%

X-Ware: mutant computing substrates

Reis

Fröhlich

Wanner

2015

2015 International Symposium on Rapid System Prototyping (RSP)

View full text Add to dashboard Cite

show abstract

“…For instance, KVM [7] integrates the VMM with the host OS, and schedules VCPUs together with other tasks in the host OS. Hence, in principle, any real-time multicore Linux scheduler [13,16,19,22,30] could be configured to apply two-level hierarchical scheduling in KVM, but with limited server mechanism support. As an example, Checconi et al [20] implemented a partitioned-queue EDF scheduler for scheduling multicore KVM virtual machines, using hard constant-bandwidth servers for the VCPUs and global fixed-priority scheduling for the guest OS scheduler.…”

Section: Systems Perspectivementioning

confidence: 99%

Real-time multi-core virtual machine scheduling in xen

et al. 2014

Proceedings of the 14th International Conference on Embedded Software

View full text Add to dashboard Cite

Recent years have witnessed two major trends in the development of complex real-time embedded systems. First, to reduce cost and enhance flexibility, multiple systems are sharing common computing platforms via virtualization technology, instead of being deployed separately on physically isolated hosts. Second, multicore processors are increasingly being used in real-time systems. The integration of real-time systems as virtual machines (VMs) atop common multicore platforms raises significant new research challenges in meeting the real-time performance requirements of multiple systems. This paper advances the state of the art in real-time virtualization by designing and implementing RTXen 2.0, a new real-time multicore VM scheduling framework in the popular Xen virtual machine monitor (VMM). RT-Xen 2.0 realizes a suite of real-time VM scheduling policies spanning the design space. We implement both global and partitioned VM schedulers; each scheduler can be configured to support dynamic or static priorities and to run VMs as periodic or deferrable servers. We present a comprehensive experimental evaluation that provides important insights into real-time scheduling on virtualized multicore platforms: (1) both global and partitioned VM scheduling can be implemented in the VMM at moderate overhead; (2) at the VMM level, while compositional scheduling theory shows partitioned EDF (pEDF) is better than global EDF (gEDF) in providing schedulability guarantees, in our experiments their performance is reversed in terms of the fraction of workloads that meet their deadlines on virtualized multicore platforms; (3) at the guest OS level, pEDF requests a smaller total VCPU bandwidth than gEDF based on compositional scheduling analysis, and therefore using pEDF at the guest OS level leads to more schedulable workloads in our experiments; (4) a combination of pEDF in the guest OS and gEDF in the VMM -configured with deferrable server -leads to the highest fraction of schedulable task sets compared to other real-time VM scheduling policies; and (5) on a platform with a shared last-level cache, the benefits of global scheduling outweigh the cache penalty incurred by VM migration.

show abstract

“…The DSP special instruction such as LMBD (left most bit detection) is used to accelerate the task switch process. The dispatcher adopts FCFS [7] (first come first served) strategy to deal with the same priority task.…”

Section: Task Queuementioning

confidence: 99%

“…It is a challenging task to support OpenCL program model on multicore DSP for embedded application. We address this problem by firstly utilizing the LLVM (low level virtual machine) [5] and Clang [6] open source compiler to support kernel compilation and further optimization for the DSP platform; then we designed 2 Advances in Mechanical Engineering [7,8] scheduler that aimed to schedule work-item in a work group to decrease the task switching overhead. Finally, we proposed a kind of software managed CACHE method to efficiently administrate the distributed global memory which was combined through interconnections such as PCIE, SRIO (serial rapid IO), Hyperlink, and SGMII.…”

Section: Introductionmentioning

confidence: 99%

A Two-Level Task Scheduler on Multiple DSP System for OpenCL

Tian

Cai

Zhou

2014

Advances in Mechanical Engineering

View full text Add to dashboard Cite

This paper addresses the problem that multiple DSP system does not support OpenCL programming. With the compiler, runtime, and the kernel scheduler proposed, an OpenCL application becomes portable not only between multiple CPU and GPU, but also between embedded multiple DSP systems. Firstly, the LLVM compiler was imported for source-to-source translation in which the translated source was supported by CCS. Secondly, two-level schedulers were proposed to support efficient OpenCL kernel execution. The DSP/BIOS is used to schedule system level tasks such as interrupts and drivers; however, the synchronization mechanism resulted in heavy overhead during task switching. So we designed an efficient second level scheduler especially for OpenCL kernel work-item scheduling. The context switch process utilizes the 8 functional units and cross path links which was superior to DSP/BIOS in the aspect of task switching. Finally, dynamic loading and software managed CACHE were redesigned for OpenCL running on multiple DSP system. We evaluated the performance using some common OpenCL kernels from NVIDIA, AMD, NAS, and Parboil benchmarks. Experimental results show that the DSP OpenCL can efficiently exploit the computing resource of multiple cores.

show abstract

Implementation and evaluation of global and partitioned scheduling in a real-time OS

Cited by 43 publications

References 47 publications

X-Ware: mutant computing substrates

X-Ware: mutant computing substrates

Real-time multi-core virtual machine scheduling in xen

A Two-Level Task Scheduler on Multiple DSP System for OpenCL

Contact Info

Product

Resources

About