Cache-Aware Virtual Machine Scheduling on Multi-Core Architecture

Abstract

SUMMARYFacing practical limits to increasing processor frequencies, manufacturers have resorted to multi-core designs in their commercial products. In multi-core implementations, cores in a physical package share the last-level caches to improve inter-core communication. To efficiently exploit this facility, operating systems must employ cache-aware schedulers. Unfortunately, virtualization software, which is a foundation technology of cloud computing, is not yet cache-aware or does not fully exploit the locality of the last-level caches. In this paper, we propose a cache-aware virtual machine scheduler for multi-core architectures. The proposed scheduler exploits the locality of the last-level caches to improve the performance of concurrent applications running on virtual machines. For this purpose, we provide a space-partitioning algorithm that migrates and clusters communicating virtual CPUs (VCPUs) in the same cache domain. Second, we provide a time-partitioning algorithm that co-schedules or schedules in sequence clustered VCPUs. Finally, we present a theoretical analysis that proves our scheduling algorithm is more efficient in supporting concurrent applications than the default credit scheduler in Xen. We implemented our virtual machine scheduler in the recent Xen hypervisor with para-virtualized Linux-based operating systems. We show that our approach can improve performance of concurrent virtual machines by up to 19% compared to the credit scheduler.

Protocol-Aware Packet Scheduling Algorithm for Multi-Protocol Processing in Multi-Core MPL Architecture

“…To hide the latency of the main memory access, hierarchical cache subsystems have been proposed and utilized on multi-core systems [23], [24]. Network processors designed for high speed PPAs always rely extremely on cache technologies owing to the restricted CPU time budget per packet [25], [26].…”

“…In addition, the most suitable value of the parameter K can be estimated as: (24) If K < N pproc , I-Cache affinity is revealed but cores still need to process all N paccept protocols. As K ≥ N pproc , the packets of one protocol will be 'locked' on the same core in the stable state.…”

MultiCache: Multilayered Cache Implementation for I/O Virtualization

“…In order to justify their argument, they first traced a production VDI workload and found that caching below the individual VMs is effective to improve I/O performance. Capo was integrated with XenServer [28], by putting it into domain 0. Also.…”

Synchronization-Aware Virtual Machine Scheduling for Parallel Applications in Xen

“…According to the proportional-share scheduling model developed in our previous research [5], the completion time of the parallel application is as follows: The completion time then increases with Lag. This means that as the VM receives less time from the CPU at any moment than what it ideally should, the performance degrades further.…”