PPC64LE RHEL8 LTO + PGO 3.x:
https://buildbot.python.org/all/#/builders/450/builds/313

0:01:22 load avg: 7.01 [242/423/1] test_multiprocessing_fork failed (env changed) (1 min 17 sec) -- running: test_concurrent_futures (1 min 3 sec), test_multiprocessing_forkserver (1 min 19 sec)

Warning -- multiprocessing.Manager still has [<ForkProcess name='SyncManager-140' pid=225343 parent=219302 started>, <ForkProcess name='QueueManager-141' pid=225345 parent=219302 started>] active children after 5.1161000469874125 seconds

Warning -- Dangling processes: {<ForkProcess name='QueueManager-141' pid=225345 parent=219302 started>}

Warning -- multiprocessing.Manager still has [<ForkProcess name='QueueManager-141' pid=225345 parent=219302 started>, <ForkProcess name='SyncManager-143' pid=225542 parent=219302 started>] active children after 5.116447829990648 seconds

test__all__ (test.test_multiprocessing_fork.MiscTestCase) ... ok
test_answer_challenge_auth_failure (test.test_multiprocessing_fork.OtherTest) ... ok
test_deliver_challenge_auth_failure (test.test_multiprocessing_fork.OtherTest) ... ok
(...)

Another example "PPC64LE RHEL8 LTO 3.x":
https://buildbot.python.org/all/#/builders/356/builds/347

0:02:49 load avg: 9.54 [415/423/1] test_multiprocessing_spawn failed (env changed) (2 min 15 sec) -- running: test_concurrent_futures (58.1 sec), test_peg_generator (1 min 39 sec), test_gdb (47.8 sec)
Warning -- multiprocessing.Manager still has [<SpawnProcess name='SyncManager-140' pid=2395988 parent=2389351 started>, <SpawnProcess name='QueueManager-141' pid=2395999 parent=2389351 started>] active children after 5.1163996559916995 seconds
Warning -- Dangling processes: {<SpawnProcess name='QueueManager-141' pid=2395999 parent=2389351 started>}
Warning -- multiprocessing.Manager still has [<SpawnProcess name='SyncManager-143' pid=2396044 parent=2389351 started>, <SpawnProcess name='QueueManager-141' pid=2395999 parent=2389351 started>] active children after 5.115814491000492 seconds

PPC64LE RHEL8 LTO + PGO 3.x:
https://buildbot.python.org/all/#/builders/450/builds/361

0:02:28 load avg: 6.47 [398/423/1] test_multiprocessing_spawn failed (env changed) (2 min 3 sec) -- running: test_asyncio (51.1 sec), test_peg_generator (47.7 sec), test_concurrent_futures (53.3 sec)
Warning -- multiprocessing.Manager still has [<SpawnProcess name='SyncManager-40' pid=2909851 parent=2907336 started>, <SpawnProcess name='SyncManager-42' pid=2909883 parent=2907336 started>] active children after 5.115746586991008 seconds
Warning -- multiprocessing.Manager still has [<SpawnProcess name='SyncManager-44' pid=2909897 parent=2907336 started>, <SpawnProcess name='SyncManager-40' pid=2909851 parent=2907336 started>] active children after 5.117473499994958 seconds
Warning -- multiprocessing.Manager still has [<SpawnProcess name='SyncManager-40' pid=2909851 parent=2907336 started>, <SpawnProcess name='SyncManager-46' pid=2909908 parent=2907336 started>] active children after 5.116073776007397 seconds