test: test-thread-priority.c fails on Linux

[nikneym]

Hi, assertion fails at ASSERT_EQ(priority, 0) in the following:

#ifdef __linux__
  ASSERT_OK(uv_thread_getpriority(pthread_self(), &priority));
  ASSERT_EQ(priority, 0);
  ASSERT_OK(uv_thread_setpriority(pthread_self(), UV_THREAD_PRIORITY_LOWEST));
  ASSERT_OK(uv_thread_getpriority(pthread_self(), &priority));
  ASSERT_EQ(priority, (0 - UV_THREAD_PRIORITY_LOWEST * 2));
#endif

make check output:

not ok 355 - thread_priority
# exit code 134
# Output from process `thread_priority`:
# Assertion failed in test/test-thread-priority.c on line 92: `priority == 0` (6 == 0)

• Version: HEAD
• Platform: Linux 6.8.0-76060800daily20240311-generic x86_64 GNU/Linux

[bnoordhuis]

The test makes the (perhaps somewhat naive) assumption that the main thread is created with a priority of 0. Do you happen to know what scheduling policy and priority were used when you ran the test?

The fix is probably quite simple:

diff --git a/test/test-thread-priority.c b/test/test-thread-priority.c
index 0aaf2977..769b485e 100644
--- a/test/test-thread-priority.c
+++ b/test/test-thread-priority.c
@@ -88,8 +88,6 @@ TEST_IMPL(thread_priority) {
  * test set nice value for the calling thread with default schedule policy
 */
 #ifdef __linux__
-  ASSERT_OK(uv_thread_getpriority(pthread_self(), &priority));
-  ASSERT_EQ(priority, 0);
   ASSERT_OK(uv_thread_setpriority(pthread_self(), UV_THREAD_PRIORITY_LOWEST));
   ASSERT_OK(uv_thread_getpriority(pthread_self(), &priority));
   ASSERT_EQ(priority, (0 - UV_THREAD_PRIORITY_LOWEST * 2));

[nikneym]

The test makes the (perhaps somewhat naive) assumption that the main thread is created with a priority of 0. Do you happen to know what scheduling policy and priority were used when you ran the test?

I don't know how to do this. Where should I look while tests are running?

I've applied the diff and it fails with the following:

not ok 355 - thread_priority
# exit code 134
# Output from process `thread_priority`:
# Assertion failed in test/test-thread-priority.c on line 93: `uv_thread_setpriority(pthread_self(), UV_THREAD_PRIORITY_LOWEST) == 0` (-13 == 0)

[bnoordhuis]

That -13 error suggests it's a permission error. Can you run strace -o trace.log -f build/uv_run_tests_a thread_priority thread_priority and post the contents of trace.log?

[nikneym]

Hi, sorry for the late reply. Directory named build has not created actually, I'm using make to build and test things. Should I switch to cmake?

[bnoordhuis]

No, that's okay. As long as you can strace the test.