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PULP Freertos with LLVM

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Status: Available


Real-time systems are systems that need to guarantee certain time constraints such as for example responding within a certain time frame. This means that computations not only need to be logically correct but also the physical instant of the result computation has to meet a particular timing constraint.

Regular general-purpose operating systems such as Linux are often not designed to ensure that real-time constraints are respected.

To address that problem several so called real-time operating systems have been developed in the last decades and used in several fields where the design of safety-critical systems matters (automotive and aerospace above all).

ControlPULP is an open-source HW/SW platform based on PULP [1], a parallel embedded MCU implementing the RISC-V ISA. ControlPULP has been developed to serve as an integrated power controller for HPC processors [2]. In this scenario, a timely response from multiple MIMO interfaces is required to be able to track and set the operating point of the controlled system in a workload-aware manner.

Currently, we support FreeRTOS [5] in ControlPULP as real-time operating system using our custom compiler toolchain based on GCC [3] which supports various extension that are implemented in our cores. We also started using LLVM [6], another large popular compiler framework, in our research group.


The goal of this project is to port PULP FreeRTOS so that it can also be compiled with LLVM:

  • Review and study ControlPULP SystemVerilog code [4]
  • (Optional) If you prefer to develop on an FPGA set up the ControlPULP FPGA flow
  • Review and study PULP FreeRTOS.
  • Port the project LLVM.
  • Compare LLVM against GCC PULP FreeRTOS with various benchmarks. ControlPULP can be easily emulated on an FPGA (ZCU102) and can execute compiled code on it.


  • 15% Literature / architecture review
  • 65% Software layer
  • 20% Evaluation


  • Experience with digital design in SystemVerilog as taught in VLSI I
  • Basic knowledge of operating systems
  • Knowledge of C programming language and unix tooling as from previous bachelor/master courses



[2] ControlPULP: A RISC-V Power Controller for HPC Processors with Parallel Control-Law Computation Acceleration