A Distributed Run-Time Environment For The Kalray Mppar (R)-256 Integrated Manycore Processor

The Kalray MPPAR (R)-256 is a single-chip manycore processor that integrates 256 user cores and 32 system cores in 28nm CMOS technology. These cores are distributed across 16 compute clusters of 16+1 cores, and 4 quad-core I/O subsystems. Each compute cluster and I/O subsystem owns a private address space, while communication and synchronization between them is ensured by data and control Networks-on-Chip (NoC). This processor targets embedded applications whose programming models fall within the following classes: Kahn Process Networks (KPN), as motivated by media processing; single program multiple data (SPMD), traditionally used for numerical kernels; and time-triggered control systems.We describe a run-time environment that supports these classes of programming models and their composition. This environment combines classic POSIX single-process multi-threaded execution inside the compute clusters and I/O subsystems, with a set of specific Inter-Process Communication (IPC) primitives that exploit the NoC architecture. We combine these primitives in order to provide the run-time support for the different target programming models. Interestingly enough, all these NoC-specific IPC primitives can be mapped to a subset of the classic synchronous and asynchronous POSIX file descriptor operations. This design thus extends the canonical 'pipe-and-filters' software component model, where POSIX processes are the atomic components, and IPC instances are the connectors.