Safe multicore scheduling in a Linux cluster environment


One Line Summary

The Linux scheduler has become fairly complex and is not always able to preserve work-conservation. We present Ipanema, a DSL to write simple and safe schedulers with proven properties.


Modern clusters rely on servers containing dozens of cores that have high infrastructure cost and energy consumption. Therefore, it is economically essential to exploit their full potential at both the application and the system level. While today’s clusters typically rely on Linux, recent research shows that the Linux scheduler suffers from performance bugs that lead to core under-usage. The consequences are wasted energy, bad infrastructure usage, and lower service response time.

The fundamental source of such performance bugs is that the Linux scheduler, being monolithic, has become too complex. In this talk, we present ongoing work on the Ipanema project that proposes to switch to a set of simple schedulers, each tailored to a specific application. Our vision raises scientific challenges in terms of easily developing schedulers and proving them safe. The key to our approach is designing a Domain-Specific Language for multicore kernel scheduling policy development, associated verification tools and a Linux runtime system.


multicore, performance, safety, scheduling, DSL

Presentation Materials



  • Me

    Jean-Pierre Lozi

    Oracle Labs


    Jean-Pierre Lozi is a Principal Member of the Technical Staff at Oracle Labs Zurich, working on distributed graph processing (PGX.D). He was formerly an Associate Professor at the University of Nice Sophia Antipolis in France, where he was working on multicore architectures, lock and synchronization algorithms, and OS schedulers.