On Sat, Dec 11, 2021 at 7:32 PM David Gow davidgow@google.com 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@google.com

Reviewed-by: Daniel Latypov dlatypov@google.com

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@goo...

• 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