Porting Barrelfish to the TileraTILEPro64 Architecture

Abstract: Barrelfish is a research operating system with the focus on the scalability of manycore architectures and the increasing numbers of heterogeneous hardware. Instead of heavily relying on the cache coherency protocol which has been proved to be an inherent bottleneck on manycore systems, Barrelfish employs the thought of distributed systems and uses the message-passing approach to implement inter-core communication. The TilePro architecture is a manycore system with up to 64 cores and several mesh networks. Because of its special hardware design, TilePro is considered to be a ideal vehicle to run Barrelfish on, in order to make full use of the advantages from its manycore and network structure. The porting of Barrelfish on TilePro architecture involves some general set-ups of image booting, virtual memory system, context switch, interrupts and system calls, inter-dispatcher communication and so on. At the beginning, the whole system fully starts up on the first logic core, and later the monitor process on the first core will be responsible for booting up others in order, according to the pre-configuration of memory space on the initial core. There are two sorts of communication provided originally in Barrelfish under the protocol of user remote procedure call (URPC). The local message passing (LMP), which happens when two dispatchers communicate with each other on the same core, is implemented by invoking system calls, passing all the values through reserved registers. The user-level message passing (UMP), which is designed for inter-core communication, depends on a shared memory approach. The inter-core communication begins as the second core is starting. The project also investigates how to utilize TilePro mesh network structure to fulfil the inter-core communication so that the characteristic of the architecture would be exploited thoroughly. TilePro offers several mesh networks with different properties and behaviours. In this case, we mainly use user dynamic network (UDN) instead of UMP to carry out remote core-to-core communication, although still based on the existing protocol of URPC. The result shows that Barrelfish can completely boots up on two cores at least and some user applications could be executed either on the first core or on the second properly, while the core-to-core communication is working on TilePro UDN network.