Thread Weaving: Static Resource Scheduling for Multithreaded High-Level Synthesis

In high-level synthesis (HLS), software multithreading constructs can be used to explicitly specify coarse-grained parallelism for multiple accelerators. While software threads typically operate independently and in isolation of each other on CPUs, HLS threads/accelerators are sub-components of one circuit. Since these components generally reside in the same clock domain, we can schedule their execution statically to avoid shared-resource contention among threads. We propose thread weaving, a technique that statically interleaves requests from different threads through scheduling constraints. With the guarantee of a contention-free schedule, we eliminate replication/arbitration of shared resources, reducing the area footprint of the circuit and improving its maximum operating frequency (F-max).