TierBPF: Page Migration Admission Control for Tiered Memory via eBPF

TL;DR

TierBPF is an eBPF-based mechanism that improves memory tiering decisions by considering page size and hardware topology, leading to significant throughput gains.

Contribution

It introduces a flexible, lightweight, eBPF-based approach for enhanced page admission control in memory tiering systems.

Findings

Achieves up to 17.7% throughput improvement.

Provides up to 75% performance gains for specific workloads.

Successfully integrated into three memory tiering systems.

Abstract

Existing software-based memory tiering systems decide which pages to place on the slower or faster tier. However, they do not take into account two important factors that greatly influence application performance: the size of the migrated pages, and the underlying hardware device and tiering topology. We introduce TierBPF, a software mechanism that can be plugged into existing memory tiering systems to take these factors into account, by making simple binary page admission decisions. TierBPF is implemented as a set of eBPF hooks, which allow users to define their own custom policies. In order to make its decisions, TierBPF utilizes a lightweight tracking mechanism for page profiling which is not dependent on the application's working set size. TierBPF, integrated into three memory tiering systems and evaluated with 17 workloads, achieves geomean throughput gains of up to 17.7% with improvements of up to 75% for individual workloads.