Skip to content

bpo-45310: Fix parrallel shared memory tests #28661

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Oct 1, 2021
Merged

bpo-45310: Fix parrallel shared memory tests #28661

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
69ebc33
bpo-45310: Fix parrallel shared memory tests
serhiy-storchaka Sep 30, 2021
f425471
Apply suggestions from code review
serhiy-storchaka Oct 1, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
40 changes: 24 additions & 16 deletions Lib/test/_test_multiprocessing.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3773,12 +3773,19 @@ def _attach_existing_shmem_then_write(shmem_name_or_obj, binary_data):
local_sms.buf[:len(binary_data)] = binary_data
local_sms.close()

def _new_shm_name(self, prefix):
# Add a PID to the name of a POSIX shared memory object to allow
# running multiprocessing tests (test_multiprocessing_fork,
# test_multiprocessing_spawn, etc) in parallel.
return prefix + str(os.getpid())

def test_shared_memory_basics(self):
sms = shared_memory.SharedMemory('test01_tsmb', create=True, size=512)
name_tsmb = self._new_shm_name('test01_tsmb')
sms = shared_memory.SharedMemory(name_tsmb, create=True, size=512)
Comment on lines +3783 to +3784
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

You may add an helper method which create a name and calls SharedMemory() with it. Or leave the code as it is, it's up to you.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It is used not only with SharedMemory, but with ShareableList.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ah, I didn't notice. It's just a minor coding style suggestion. The code is good as it is.

self.addCleanup(sms.unlink)

# Verify attributes are readable.
self.assertEqual(sms.name, 'test01_tsmb')
self.assertEqual(sms.name, name_tsmb)
self.assertGreaterEqual(sms.size, 512)
self.assertGreaterEqual(len(sms.buf), sms.size)

Expand All @@ -3798,12 +3805,12 @@ def test_shared_memory_basics(self):
self.assertEqual(sms.buf[0], 42)

# Attach to existing shared memory segment.
also_sms = shared_memory.SharedMemory('test01_tsmb')
also_sms = shared_memory.SharedMemory(name_tsmb)
self.assertEqual(also_sms.buf[0], 42)
also_sms.close()

# Attach to existing shared memory segment but specify a new size.
same_sms = shared_memory.SharedMemory('test01_tsmb', size=20*sms.size)
same_sms = shared_memory.SharedMemory(name_tsmb, size=20*sms.size)
self.assertLess(same_sms.size, 20*sms.size) # Size was ignored.
same_sms.close()

Expand All @@ -3821,7 +3828,7 @@ def test_shared_memory_basics(self):
'multiprocessing.shared_memory._make_filename') as mock_make_filename:

NAME_PREFIX = shared_memory._SHM_NAME_PREFIX
names = ['test01_fn', 'test02_fn']
names = [self._new_shm_name('test01_fn'), self._new_shm_name('test02_fn')]
# Prepend NAME_PREFIX which can be '/psm_' or 'wnsm_', necessary
# because some POSIX compliant systems require name to start with /
names = [NAME_PREFIX + name for name in names]
Expand All @@ -3843,17 +3850,17 @@ def test_shared_memory_basics(self):
# manages unlinking on its own and unlink() does nothing).
# True release of shared memory segment does not necessarily
# happen until process exits, depending on the OS platform.
name_dblunlink = self._new_shm_name('test01_dblunlink')
sms_uno = shared_memory.SharedMemory(
name_dblunlink,
create=True,
size=5000
)
with self.assertRaises(FileNotFoundError):
sms_uno = shared_memory.SharedMemory(
'test01_dblunlink',
create=True,
size=5000
)

try:
self.assertGreaterEqual(sms_uno.size, 5000)

sms_duo = shared_memory.SharedMemory('test01_dblunlink')
sms_duo = shared_memory.SharedMemory(name_dblunlink)
sms_duo.unlink() # First shm_unlink() call.
sms_duo.close()
sms_uno.close()
Expand All @@ -3865,7 +3872,7 @@ def test_shared_memory_basics(self):
# Attempting to create a new shared memory segment with a
# name that is already in use triggers an exception.
there_can_only_be_one_sms = shared_memory.SharedMemory(
'test01_tsmb',
name_tsmb,
create=True,
size=512
)
Expand All @@ -3879,7 +3886,7 @@ def test_shared_memory_basics(self):
# case of MacOS/darwin, requesting a smaller size is disallowed.
class OptionalAttachSharedMemory(shared_memory.SharedMemory):
_flags = os.O_CREAT | os.O_RDWR
ok_if_exists_sms = OptionalAttachSharedMemory('test01_tsmb')
ok_if_exists_sms = OptionalAttachSharedMemory(name_tsmb)
self.assertEqual(ok_if_exists_sms.size, sms.size)
ok_if_exists_sms.close()

Expand Down Expand Up @@ -4084,10 +4091,11 @@ def test_shared_memory_ShareableList_basics(self):
self.assertEqual(sl.count(b'adios'), 0)

# Exercise creating a duplicate.
sl_copy = shared_memory.ShareableList(sl, name='test03_duplicate')
name_duplicate = self._new_shm_name('test03_duplicate')
sl_copy = shared_memory.ShareableList(sl, name=name_duplicate)
try:
self.assertNotEqual(sl.shm.name, sl_copy.shm.name)
self.assertEqual('test03_duplicate', sl_copy.shm.name)
self.assertEqual(name_duplicate, sl_copy.shm.name)
self.assertEqual(list(sl), list(sl_copy))
self.assertEqual(sl.format, sl_copy.format)
sl_copy[-1] = 77
Expand Down