The --jobs parameter for kunit_tool currently defaults to 8 CPUs, regardless of the number available. For systems with significantly more (or less), this is not as efficient. Instead, default --jobs to the number of CPUs available to the process: while there are as many superstitions as to exactly what the ideal jobs:CPU ratio is, this seems sufficiently sensible to me. A new helper function to get the default number of jobs is added: get_default_jobs() -- this is used in kunit_tool_test instead of a hardcoded value, or an explicit call to len(os.sched_getaffinity()), so should be more flexible if this needs to change in the future. Signed-off-by: David Gow <davidgow@xxxxxxxxxx> --- Changes since v1: https://lore.kernel.org/linux-kselftest/20211211084928.410669-1-davidgow@xxxxxxxxxx/ - Use len(os.sched_getaffinity()) instead of os.cpu_count(), which gives the number of available processors (to this process), rather than the total. - Fix kunit_tool_test.py, which had 8 jobs hardcoded in a couple of places. - Thanks to Daniel Latypov for these suggestions. --- tools/testing/kunit/kunit.py | 5 ++++- tools/testing/kunit/kunit_tool_test.py | 5 +++-- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/tools/testing/kunit/kunit.py b/tools/testing/kunit/kunit.py index 68e6f461c758..6b0ddd6d0115 100755 --- a/tools/testing/kunit/kunit.py +++ b/tools/testing/kunit/kunit.py @@ -264,6 +264,9 @@ def massage_argv(argv: Sequence[str]) -> Sequence[str]: return f'{arg}={pseudo_bool_flag_defaults[arg]}' return list(map(massage_arg, argv)) +def get_default_jobs() -> int: + return len(os.sched_getaffinity(0)) + def add_common_opts(parser) -> None: parser.add_argument('--build_dir', help='As in the make command, it specifies the build ' @@ -310,7 +313,7 @@ def add_build_opts(parser) -> None: parser.add_argument('--jobs', help='As in the make command, "Specifies the number of ' 'jobs (commands) to run simultaneously."', - type=int, default=8, metavar='jobs') + type=int, default=get_default_jobs(), metavar='jobs') def add_exec_opts(parser) -> None: parser.add_argument('--timeout', diff --git a/tools/testing/kunit/kunit_tool_test.py b/tools/testing/kunit/kunit_tool_test.py index 9c4126731457..512936241a56 100755 --- a/tools/testing/kunit/kunit_tool_test.py +++ b/tools/testing/kunit/kunit_tool_test.py @@ -419,7 +419,7 @@ class KUnitMainTest(unittest.TestCase): def test_build_passes_args_pass(self): kunit.main(['build'], self.linux_source_mock) self.assertEqual(self.linux_source_mock.build_reconfig.call_count, 0) - self.linux_source_mock.build_kernel.assert_called_once_with(False, 8, '.kunit', None) + self.linux_source_mock.build_kernel.assert_called_once_with(False, kunit.get_default_jobs(), '.kunit', None) self.assertEqual(self.linux_source_mock.run_kernel.call_count, 0) def test_exec_passes_args_pass(self): @@ -525,8 +525,9 @@ class KUnitMainTest(unittest.TestCase): def test_build_builddir(self): build_dir = '.kunit' + jobs = kunit.get_default_jobs() kunit.main(['build', '--build_dir', build_dir], self.linux_source_mock) - self.linux_source_mock.build_kernel.assert_called_once_with(False, 8, build_dir, None) + self.linux_source_mock.build_kernel.assert_called_once_with(False, jobs, build_dir, None) def test_exec_builddir(self): build_dir = '.kunit' -- 2.34.1.173.g76aa8bc2d0-goog
