libmem - A Dynamic Memory Allocation library for High-Level Synthesis designs.

What is libmem

This C library has 5 different dynamic memory allocation schemes, suitable for software and HLS designers (even though the purpose of this library was intended to serve the latter case). Our library is configurable on a minimum request size.

1. libgnumem.c: An allocator which inherits most of it's logic from Doug Lea's malloc & free.
2. liblinmem.c: A linear allocator which 'bumps' up a pointer by an incoming request size to the next available free region of memory.
3. libbitmem.c: A bitmap allocator, which configurable minimum request size.
4. libbudmem.c: A buddy allocator, which is configurable on minimum request size.
5. liblutmem.c: A LUT-like allocator, where a request size is mapped to a corresponding set of preallocated address, stored in a LUT.

We also include the LLVM-Transformation Pass which was outlined in Dynamic Memory Allocation Techniques for High-Level Synthesis. This pass is able to convert stack allocated arrays into dynamic memory calls in order to reduce BRAM pressure within an FPGA. This pass lives in transformation

Why do we need libmem

For a beginner HLS developer wishing to port over designs using dynamic memory, it is not straightforward or easy to migrate designs to a static memory requirement. With this library, we patch this concern.

Is there an evaluation suite?

Yes, I have linked a separate repository which includes a suite of benchmarks (suitable for performance checking with HLS tools) This link is here!

Notes

This library doesn't use off-chip memory. It strings together a bunch of BRAMs and uses this as a heap.

This library is associated with this publication: Nicholas Giamblanco and Jason Anderson. A Dynamic Memory Allocation Library for High-Level Synthesis. In 2019 29th International Conference on Field Programmable Logic and Applications (FPL). IEEE, 2019

Author

Nicholas V. Giamblanco, M.A.Sc. (2019)