Fast local page-tables for virtualized NUMA servers with vMitosis

Panwar, A and Achermann, R and Basu, A and Bhattacharjee, A and Gopinath, K and Gandhi, J (2021) Fast local page-tables for virtualized NUMA servers with vMitosis. In: 26th ACM International Conference on Architectural Support for Programming Languages and Operating Systems, ASPLOS 2021, 19-23 Apr 2021, pp. 194-210.

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Abstract

Increasing heterogeneity in the memory system mandates careful data placement to hide the non-uniform memory access (NUMA) effects on applications. However, NUMA optimizations have predominantly focused on application data in the past decades, largely ignoring the placement of kernel data structures due to their small memory footprint; this is evident in typical OS designs that pin kernel objects in memory. In this paper, we show that careful placement of kernel data structures is gaining importance in the context of page-tables: Sub-optimal placement of page-tables causes severe slowdown (up to 3.1x) on virtualized NUMA servers. In response, we present vMitosis- A system for explicit management of two-level page-tables, i.e., the guest and extended page-tables, on virtualized NUMA servers. vMitosis enables faster address translation by migrating and replicating page-tables. It supports two prevalent virtualization configurations: First, where the hypervisor exposes the NUMA architecture to the guest OS, and second, where such information is hidden from the guest OS. vMitosis is implemented in Linux/KVM, and our evaluation on a recent 1.5TiB 4-socket server shows that it effectively eliminates NUMA effects on 2D page-table walks, resulting in a speedup of 1.8-3.1x for Thin (single-socket) and 1.06-1.6x for Wide (multi-socket) workloads. © 2021 ACM.

Item Type:	Conference Paper
Publication:	International Conference on Architectural Support for Programming Languages and Operating Systems - ASPLOS
Publisher:	Association for Computing Machinery
Additional Information:	The copyright for this article belongs to Association for Computing Machinery
Keywords:	Data structures; Linux; Titanium compounds, Address translation; Application data; Data placement; Memory systems; Non uniform memory access; Numa architectures; Optimal placements; Small memory footprint, Memory architecture
Department/Centre:	Division of Electrical Sciences > Computer Science & Automation
Date Deposited:	11 Aug 2021 09:10
Last Modified:	11 Aug 2021 09:10
URI:	http://eprints.iisc.ac.in/id/eprint/69097

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