An efficient virtual CPU scheduling in cloud computing

Jang, Jyongsik; Jung, Jinman; Hong, Jiman

doi:10.1007/s00500-019-04551-w

Cited by 8 publications

(9 citation statements)

References 20 publications

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“…The major mechanisms involved in Xen's I/O procedure are the shared ring buffer and event channel [11,18,[21][22][23]. The shared ring buffer provides a shared memory communication mechanism that is used for communication among VMs and between DOM0 and guest VMs.…”

Section: Xen's I/o Proceduresmentioning

confidence: 99%

“…Some researchers have noted that in a virtualized environment with limited resources, as the number of VMs increases, the number of vCPUs placed in the run-queue also increases, resulting in I/O latency [7,10,[20][21][22][25][26][27]. This indicates that when an unpredictable I/O occurs on a specific VM, I/O latency rises until all vCPUs placed in front of the VM's vCPU are scheduled.…”

Section: Motivationmentioning

confidence: 99%

“…However, without considering the workload type of the VM, allocating a relatively long time slice to all VMs increases the average run-queue waiting time for all vCPUs in the run-queue, including I/O-intensive vCPUs, resulting in I/O latency for I/O-intensive VMs. Further, concurrently executing a CPU-intensive workload and an I/O-intensive workload in the VM affects I/O performance [18,22,31,32]. For VMs with mixed workloads that perform CPU-intensive and I/O-intensive tasks simultaneously, when the vCPU processes I/O responses from DOM0, it may not complete the processing of tasks for I/O in the current scheduling round.…”

Section: Motivationmentioning

confidence: 99%

“…and disk-intensive services (e.g., big data services, image processing services, etc.) [15,18,20,22,33]. To overcome these limitations of the existing virtualized environment, we introduce ISACS to address the aforementioned limitations of existing virtualized environments.…”

Section: Meaningless Prioritymentioning

confidence: 99%

“…Jang et al [22] presented a loan and redeem mechanism in the Credit1 scheduler through the BOOST controlling method. They allocated BOOST credits derived from the previous scheduling round to all vCPUs in the current round; this process considers the BOOST frequency to control the I/O resource sharing of I/O-intensive VMs.…”

Section: Related Workmentioning

confidence: 99%

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I/O Strength-Aware Credit Scheduler for Virtualized Environments

Lee

2020

Electronics

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With the evolution of cloud technology, the number of user applications is increasing, and computational workloads are becoming increasingly diverse and unpredictable. However, cloud data centers still exhibit a low I/O performance because of the scheduling policies employed, which are based on the degree of physical CPU (pCPU) occupancy. Notably, existing scheduling policies cannot guarantee good I/O performance because of the uncertainty of the extent of I/O occurrence and the lack of fine-grained workload classification. To overcome these limitations, we propose ISACS, an I/O strength-aware credit scheduler for virtualized environments. Based on the Credit2 scheduler, ISACS provides a fine-grained workload-aware scheduling technique to mitigate I/O performance degradation in virtualized environments. Further, ISACS uses the event channel mechanism in the virtualization architecture to expand the scope of the scheduling information area and measures the I/O strength of each virtual CPU (vCPU) in the run-queue. Then, ISACS allocates two types of virtual credits for all vCPUs in the run-queue to increase I/O performance and concurrently prevent CPU performance degradation. Finally, through I/O load balancing, ISACS prevents I/O-intensive vCPUs from becoming concentrated on specific cores. Our experiments show that compared with existing virtualization environments, ISACS provides a higher I/O performance with a negligible impact on CPU performance.

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Section: Xen's I/o Proceduresmentioning

confidence: 99%