On Sat, Dec 11, 2021 at 7:32 PM David Gow <davidgow@xxxxxxxxxx> wrote: > > 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> Reviewed-by: Daniel Latypov <dlatypov@xxxxxxxxxx> Looks good to me. I played around with a few commands like $ taskset 0x3 ./tools/testing/kunit/kunit.py run and saw it pick the pass the expected --jobs value to make. > --- > > 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 >
