Abstract: Parallel data processing may include map and reduce processes. Map processes may include at least one input thread and at least one output thread. Input threads may apply map operations to produce key/value pairs from input data blocks. These pairs may be sent to internal shuffle units which distribute the pairs, sending specific pairs to particular output threads. Output threads may include multiblock accumulators to accumulate and/or multiblock combiners to combine values associated with common keys in the key/value pairs. Output threads can output intermediate pairs of keys and combined values. Likewise, reduce processes may access intermediate key/value pairs using multiple input threads. Reduce operations may be applied to the combined values associated with each key. Reduce processes may contain internal shuffle units that distributes key/value pairs and sends specific pairs to particular output threads. These threads then produce the final output.

Abstract: A method and apparatus for marking a region of source code within a program unit and extracting an executable version of this marked region of code. The executable version has a initialized program state equivalent to that of the original source code when the original source code entered the region. The method and apparatus remove as much source code as possible from the original source code while retaining enough code to enable the extracted region execute (replay) in a manner identical to the execution of the program region in the context of the original system.