1989 Reports

A Critique of the llc Parallel Language and Some Solutions

Mills, Russell C.

llc is an extension of C that has been implemented on the Dado2 machine at Columbia University. In an llc program, a single controlling processor invokes operations in parallel in subsets of a set of attached processors, which themselves can invoke parallel operations in remaining processors. llc allocates one element of a parallel object per physical processor. Removing this restriction allows programs to use parallel vectors of arbitrary size without reference to the number of processors in the machine. A program in the resulting language, mpc, contains a single main process. Each mpc process can create sets of attached processes statically or dynamically by declaring arrays of process type, and can invoke operations in parallel in these processes. mpc retains much of llc's power while adding generality, clarity, and portability.