Fine-grained I/O fairness analysis in virtualized environments

Kim, Sewoog; Kang, Dong-Woo; Choi, Jongmoo

doi:10.1145/2401603.2401690

Cited by 2 publications

(3 citation statements)

References 8 publications

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“…The placement state of vCPUs with different workloads affects the workload tendencies of the run-queue itself; hence, the I/O guarantee degree varies depending on which run-queue the I/O-intensive vC-PUs are placed. This leads to unfair I/O performance between VMs when there is I/O resource contention [12], [14], [20] [26]. Such situations cause a scheduling dependency problem leading to unpredictable and inconsistent I/O performance of VMs depending on the workload tendency of neighboring vCPUs in the virtualized system with a high VM density.…”

Section: ) Lack Of I/o Workload Intensity Awarenessmentioning

confidence: 99%

“…The hypervisor's vCPU scheduling policy, which schedules each vCPU based on the degree of pCPU occupancy, provides highly fair CPU performance to CPU-intensive VMs [9], [10], [11]. However, a vCPU scheduler that does not consider the I/O strength of data-intensive VMs results in the unfair I/O performance of the virtualized system [9], [10], [11], [12], [13]. In addition, the current virtualized system simply adopts Linux-based I/O procedures, which leads to a lack of awareness of user-contention architectures, resulting in internal unfair I/O resource usage in virtualized systems [14] [15].…”

Section: Introductionmentioning

confidence: 99%

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Fine-Grained I/O Traffic Control Middleware for I/O Fairness in Virtualized System

Lee

2022

IEEE Access

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The development of IT technology in the 21st century has created a new paradigm for real-time, data-intensive user services, such as connected cars, smart factories, and remote health care services. The considerable computational resources required by these services are rendering the cloud increasingly more important. In the cloud server, user services are forced to share physical resources because of the emerging resource competition, thus introducing various types of unpredictable workloads. The core technology of the cloud is a virtualized system, which isolates and shares the powerful physical resources of the server in the form of a virtual machine (VM) to increase resource efficiency. However, the scheduling policy of a virtual CPU (vCPU), which is a logical CPU of a VM, generally schedules the vCPU based on the degree of occupation of the physical CPU (pCPU) without regarding I/O strength; so it brings the unfair I/O performance among VMs in the virtualized systems. The user services performing on the VM are not aware of the user-contention architectures, which sharing of I/O devices, in the virtualized systems; Furthermore, the current virtualized system simply adopts the Linux-based I/O processing process which optimized for user-contention-free architectures. Therefore, the architecture that brings the unfair usage of I/O devices among user services is hardly regarded and has low awareness in current virtualized systems. To overcome this problem, in this study, I-Balancer is presented to provide fair I/O performance among I/O-intensive user services by applying an asynchronous inter-communication control technique for the virtualized system with a high VM density. The main design goal of I-Balancer is to increase the awareness of user-contention architectures in the hypervisor. I-Balancer derives the fine-grained workload and I/O strength for each vCPU during the scheduler and event channel areas. Subsequently, to strengthen fair I/O performance, an I/O traffic control mechanism is implemented to control the inter-domain communication traffic according to the I/O strength of the VMs. The experimental results prove that I-Balancer provides a fairer network and disk I/O performance than the existing virtualized systems with negligible performance interference and overhead.

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Section: ) Lack Of I/o Workload Intensity Awarenessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fine-Grained I/O Traffic Control Middleware for I/O Fairness in Virtualized System

Lee

2022

IEEE Access

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“…In [5], we have proposed the analysis tool only, while in this paper, we investigate the analysis results in depth, design a new virtualization-aware I/O scheduler, and evaluate its effectiveness through implementationbased experiments.…”

Section: Related Workmentioning

confidence: 99%

Revisiting I/O Scheduler for Enhancing I/O Fairness in Virtualization Systems

Kim

Kang

Choi

2014

IEICE Trans. Inf. & Syst.

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SUMMARYAs the virtualization technology becomes the core ingredient for recent promising IT infrastructures such as utility computing and cloud computing, accurate analysis of the internal behaviors of virtual machines becomes more and more important. In this paper, we first propose a novel I/O fairness analysis tool for virtualization systems. It supports the following three features: fine-grained, multimodal and multidimensional. Then, using the tool, we observe various I/O behaviors in our experimental XEN-based virtualization system. Our observations disclose that 1) I/O fairness among virtual machines is broken frequently even though each virtual machine requests the same amount of I/Os, 2) the unfairness is caused by an intricate combination of factors including I/O scheduling, CPU scheduling and interactions between the I/O control domain and virtual machines, and 3) some mechanisms, especially the CFQ (Completely Fair Queuing) I/O scheduler that supports fairness reasonable well in a nonvirtualization system, do not work well in a virtualization system due to the virtualization-unawareness. These observations drive us to design a new virtualization-aware I/O scheduler for enhancing I/O fairness. It gives scheduling opportunities to asynchronous I/Os in a controlled manner so that it can avoid the unfairness caused by the priority inversion between the low-priority asynchronous I/Os and high-priority synchronous I/Os. Real implementation based experimental results have shown that our proposal can enhance I/O fairness reducing the standard deviation of the finishing time among virtual machines from 4.5 to 1.2.

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Fine-grained I/O fairness analysis in virtualized environments

Cited by 2 publications

References 8 publications

Fine-Grained I/O Traffic Control Middleware for I/O Fairness in Virtualized System

Fine-Grained I/O Traffic Control Middleware for I/O Fairness in Virtualized System

Revisiting I/O Scheduler for Enhancing I/O Fairness in Virtualization Systems

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