Title
ghOSt: Fast & Flexible User-Space Delegation of Linux Scheduling
Abstract
ABSTRACTWe present ghOSt, our infrastructure for delegating kernel scheduling decisions to userspace code. ghOSt is designed to support the rapidly evolving needs of our data center workloads and platforms. Improving scheduling decisions can drastically improve the throughput, tail latency, scalability, and security of important workloads. However, kernel schedulers are difficult to implement, test, and deploy efficiently across a large fleet. Recent research suggests bespoke scheduling policies, within custom data plane operating systems, can provide compelling performance results in a data center setting. However, these gains have proved difficult to realize as it is impractical to deploy a custom OS image(s) at an application granularity, particularly in a multi-tenant environment, limiting the practical applications of these new techniques. ghOSt provides general-purpose delegation of scheduling policies to userspace processes in a Linux environment. ghOSt provides state encapsulation, communication, and action mechanisms that allow complex expression of scheduling policies within a userspace agent, while assisting in synchronization. Programmers use any language to develop and optimize policies, which are modified without a host reboot. ghOSt supports a wide range of scheduling models, from per-CPU to centralized, run-to-completion to preemptive, and incurs low overheads for scheduling actions. We demonstrate ghOSt's performance on both academic and real-world workloads, including Google Snap and Google Search. We show that by using ghOSt instead of the kernel scheduler, we can quickly achieve comparable throughput and latency while enabling policy optimization, non-disruptive upgrades, and fault isolation for our data center workloads. We open-source our implementation to enable future research and development based on ghOSt.
Year
DOI
Venue
2021
10.1145/3477132.3483542
ACM Symposium on Operating Systems Principles
DocType
Citations 
PageRank 
Conference
1
0.34
References 
Authors
0
10
Name
Order
Citations
PageRank
Jack Tigar Humphries110.34
Neel Natu210.34
Ashwin Chaugule310.34
Ofir Weisse4533.99
Barret Rhoden510.34
Josh Don610.34
Luigi Rizzo710.34
Oleg Rombakh810.34
Paul Turner9246.00
Christos Kozyrakis105817355.99