This v4 series introduces an optimized RISC-V memcmp() implementation and extends the KUnit string tests to cover both functional correctness and benchmarking of memcmp().
The memcmp() implementation incorporates review feedback from earlier versions. It features improved alignment handling, optimized loop structures, efficient use of the Zbb extension, and ensures overall correctness. The KUnit updates provide comprehensive memcmp() test coverage and a benchmark mode. This v4 specifically fixes a build error regarding an undeclared function call (STRING_BENCH). Signed-off-by: Milan Tripkovic <[email protected]> --- v4 changes: - Fixed build error: call to undeclared function 'STRING_BENCH' - Link to v3: https://lore.kernel.org/all/[email protected]/ v3 changes: - Split memcmp benchmark into wrapper (string_bench_memcmp) and worker function (do_string_bench_memcmp). - Removed all C99 mixed declarations; moved all variable declarations to the top of each function. - Converted len, iterations and loop counters in the benchmark to u64 to avoid implicit casts. - Cleaned up spacing, indentation and minor style issues. - Added #if defined(CONFIG_RISCV_ISA_ZBB)... in memcmp.S - Link to v2: https://lore.kernel.org/all/[email protected]/ v2 changes: - Added alignment checks for buffers to avoid expensive misaligned loads. - Optimized the loop using end-pointers to reduce per-iteration overhead. - Implemented word-aligned tail handling using ZBB shifts. - Removed redundant pointer equality (a0 == a1) check. - Retained BE support via #ifndef; ZBB rev8 is used for the LE fast-path. - Fixed KUnit build failures for Clang and non-benchmark configs. - Link to v1: https://lore.kernel.org/all/[email protected]/ Milan Tripkovic (2): riscv: lib: add memcmp() implementation lib/string_kunit: extend benchmarks and unit test to memcmp() arch/riscv/include/asm/string.h | 2 + arch/riscv/lib/Makefile | 1 + arch/riscv/lib/memcmp.S | 125 ++++++++++++++++++++++++++++++++ arch/riscv/purgatory/Makefile | 5 +- lib/tests/string_kunit.c | 120 ++++++++++++++++++++++++++++++ 5 files changed, 252 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/lib/memcmp.S -- 2.43.0
