The linear systems used for performance benchmarks at https://github.com/ddemidov/cppstokes_benchmarks. The files correspond to the Stokes equation discretized for 3 different cases: Unit cube problem (ucube). A rotating flow driven by an external force f in a closed unit cube. Converging-diverging tube problem (cdtube). Pressure-driven tube flow through a 3D converging-diverging tube under a pressure drop of 1Pa. Sphere packing problem (spack). A complex sphere packing flow problem with non-uniform cell size distribution and large cell size contrast. Each problem contains the system matrix (A.bin), the RHS vector (b.bin), and the text file containing the number of DOFs corresponding to the velocity field (u.txt) for 6 to 7 different problem sizes.