Porting Cilk to the Barrelfish OS

Sammanfattning: Barrelfish operating system is an experimental instance of multikernel structure which exhibits good features such as hardware heterogeneity, scalability, dynamicity, etc. Barrelfish is in progress and lacks applications. Therefore, there is a need to investigate the efficiency of applications running in Barrelfish and one of candidates is a shared-memory application. To conduct an empirical study, Cilk is chosen inasmuch as its runtime library is designed for shared-memory architectures and it has been known to expose good performance. This thesis focuses on making Cilk run on top of Barrelfish in order to reach two goals: portability which is described to be supported by Barrelfish, and good speed afterwards. The porting involves compiling Cilk runtime source code by replacing its pthread subroutines with set of APIs in Barrelfish and then changing the way Cilk scheduler spawns worker thread on multiple cores. However, the main point of the porting is to make different cores access to the same virtual address space. Luckily, Barrelfish provides a notion of domain which specifies the number of cores in an application so that these cores can share the same memory space. This thesis also has carried out benchmarks on some Cilk programs and found that Cilk does not perform as well as it is expected. In addition measurements on parallel workers shows that Cilk on Barrelfish takes more cycles to perform computation. Although Cilk still maintains work-first principle, it cannot achieve the time bound. The spanning domain cost is proportional to the number of cores, but it will matter if applications take small time to complete.