Currently the test execution part of KUnit is very single threaded, meaning that on larger systems with many CPUs the wall clock time for running the full suite is longer than it could be. While we don't want to run multiple tests in parallel on the same kernel for stability and clarity reasons all the tests are being run in a virtual environment of some kind so we can achieve better parallelism by splitting the tests between multiple simultaneously running virtual environments. The KUnit runner already has support for splitting tests up and running either suites or individual tests in isolated guests, build on this to support parallel execution.
While developing this some existing issues became more visible, some of these are fixed with some standalone patches at the start of the series but I split some issues with test naming out, these were sent as: - lib/tests: util_macros: Drop the '.' from the KUnit suite name https://lore.kernel.org/r/[email protected] - kunit: Add KUNIT_CASE_PARAM_UNIQUE() and KUNIT_CASE_PARAM_WITH_INIT_UNIQUE() https://lore.kernel.org/r/[email protected] Performance results with --alltests, using the elapsed time reported by the KUnit runner with an already built kernel on a Raspberry Pi 5 with 4 CPUs and a Graviton 4 with 192 CPUs: default parallel per test parallel per test Raspberry Pi 5 67.7s 49.4s 836.4s 326.5s Graviton 4 64.1s 30.8s 445.9s 39.7s Even with the overhead of having to boot more kernels we are seeing substantial speedups, even on lower end systems with limited parallelism available. Signed-off-by: Mark Brown <[email protected]> --- Mark Brown (7): kunit: tool: Preserve failures from kernels without test results kunit: tool: Combine reports from isolated kernels kunit: tool: Boot with a larger log buffer when listing tests kunit: tool: Add an outfile argument to run_kernel() kunit: tool: Allow several run_kernel() calls to be in flight at once kunit: tool: Serialise output written from multiple threads kunit: tool: Add --parallel to run suites in concurrent kernels Documentation/dev-tools/kunit/run_wrapper.rst | 11 ++ tools/testing/kunit/kunit.py | 151 +++++++++++---- tools/testing/kunit/kunit_junit.py | 3 +- tools/testing/kunit/kunit_kernel.py | 78 +++++--- tools/testing/kunit/kunit_printer.py | 9 +- tools/testing/kunit/kunit_tool_test.py | 253 +++++++++++++++++++++++++- 6 files changed, 438 insertions(+), 67 deletions(-) --- base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907 base-tree: git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm master change-id: 20261012-kunit-parallel-a8a7e3c19a30 Best regards, -- Mark Brown <[email protected]>
