BSDCan2014 - Final

BSDCan 2014
The Technical BSD Conference

Zbigniew Bodek
Day Talks - Day 2 - Sat May 17 - 2014-05-17
Room Montpetit 202
Start time 13:30
Duration 01:00
ID 449
Event type Lecture
Track Embedded
Language used for presentation English

Transparent Superpages for FreeBSD on ARM

The talk covers recent work on providing transparent superpages support for the FreeBSD operating system on ARM. The concept of superpages is a virtual memory system optimization, which allow for efficient use of the TLB translations, effectively reducing the overhead related to the memory management. This technique can significantly increase system's performance at the interface between CPU and main memory thus affecting its overall efficiency.

The lecture focuses on presenting superpages mechanism supported by the FreeBSD in the context of its implementation for the ARM architecture. Principles of the virtual memory operations are briefly presented to illustrate the requirements and limitations standing before the related subsystem. The talk provides description of the virtual memory system architecture introduced in ARMv6/v7 compliant processors and the opportunities to take advantage of the superpages technique.

The primary focus of the presentation is to elaborate on how the superpages functionality was implemented on FreeBSD/arm and what are the results of its application. The talk presents real-life measurements and benchmarks performed on modern, multiprocessor ARM platforms. Hence, the actual achievements and areas of application are shown. Finally, the article summarizes the integration process to the mainline FreeBSD and discusses the areas of future work and improvements.