Apparatus and methods are disclosed for throttling processor operation in block-based processor architectures. In one example of the disclosed technology, a block-based instruction set architecture processor includes a plurality of processing cores configured to fetch and execute a sequence of instruction blocks. Each of the processing cores includes function resources for performing operations specified by the instruction blocks. The processor further includes a core scheduler configured to allocate functional resources for performing the operations. The functional resources are allocated for executing the instruction blocks based, at least in part, on a performance metric. The performance metric can be generated dynamically or statically based on branch prediction accuracy, energy usage tolerance, and other suitable metrics.