HLS-based Optimization of Tau Triggering Algorithm for LHC: a case study

With the current increase in the data produced by the Large Hadron Collider (LHC) at CERN, it becomes important to process this data in a corresponding manner. To begin with, to efficiently select events that contain relevant information from a massive flow of data. This is the task of the tau lepton decay triggering algorithm. The implementation is based on the High-Level Synthesis (HLS) approach that allows generating a hardware description of the design from the algorithm written in a high-level programming language like C++. HLS tools are intended to decrease the time and complexity of hardware design development, however, their capabilities are limited. The development of an efficient application requires substantial knowledge of the hardware design and HLS specifics. This paper presents the optimizations introduced to the algorithm that improved latency and area and more importantly solved the problems with the routing, making it possible to implement the algorithm on the FPGA fabric.