4 Commits

Author SHA1 Message Date
Jonas Devlieghere
85d6edb265 Revert "[test] Address TestConcurrentMany*.py flakiness on macOS"
This reverts my change to pseudo_barrier.h which isn't necessary anymore
after Fred's fix to debugserver and caused TestThreadStepOut to fail.

llvm-svn: 370963
2019-09-04 19:36:29 +00:00
Frederic Riss
cc5b509b9e Workaround TestConcurrentMany* flakiness in a more pricipled way
The flakiness on our local machines seems to come for a race in the kernel
between task_suspend and the creation of the Mach exceptions for the threads
that hit breakpoints. The debugserver code is written with the assumption
that the kernel will be able to provide us with all the exceptions for a
given task once task_suspend returns. On machines with higher core counts,
this seems not to be the case. The first batch of exceptions we get after
task_suspend does not contain exceptions for all the threads that have hit
a breakpoint, thus they get misreprorted in the first stop packet.

Adding a 1ms timeout to the call that retrieves the batch of exceptions
seems to workaround the issue reliably on our machines, and it shoulnd't
impact standard debugging scenarios too much (a stop will incur an additional
1ms delay). We'll be talking to the kernel team to figure out the right
contract for those APIs.

This patch also reverts part of Jonas' previous workaround for the
issue (r370785).

llvm-svn: 370916
2019-09-04 16:13:12 +00:00
Jonas Devlieghere
e44f2eb315 [test] Addres TestConcurrentMany*.py flakiness on macOS
On "fast" macOS machines, the TestConcurrentMany*.py tests would fail
randomly with different numbers of breakpoints, watchpoints, etc. This
seems to be avoidable by giving the threads a little time to breath
after the passing the synchronization barrier. This is far from a
structural fix but it reduces the flakiness.

llvm-svn: 370785
2019-09-03 17:04:04 +00:00
Pavel Labath
01a28ca7f8 Centralize libc++ test skipping logic
Summary:
This aims to replace the different decorators we've had on each libc++
test with a single solution. Each libc++ will be assigned to the
"libc++" category and a single central piece of code will decide whether
we are actually able to run libc++ test in the given configuration by
enabling or disabling the category (while giving the user the
opportunity to override this).

I started this effort because I wanted to get libc++ tests running on
android, and none of the existing decorators worked for this use case:
 - skipIfGcc - incorrect, we can build libc++ executables on android
 with gcc (in fact, after this, we can now do it on linux as well)
 - lldbutil.skip_if_library_missing - this checks whether libc++.so is
 loaded in the proces, which fails in case of a statically linked
 libc++ (this makes copying executables to the remote target easier to
 manage).

To make this work I needed to split out the pseudo_barrier code from the
force-included file, as libc++'s atomic does not play well with gcc on
linux, and this made every test fail, even though we need the code only
in the threading tests.

So far, I am only annotating one of the tests with this category. If
this does not break anything, I'll proceed to update the rest.

Reviewers: jingham, zturner, EricWF

Subscribers: srhines, lldb-commits

Differential Revision: https://reviews.llvm.org/D30984

llvm-svn: 299028
2017-03-29 21:01:14 +00:00