Re: [PATCH v4 28/40] tests/acceptance: skip multicore mips_malta tests on GitLab

[Philippe Mathieu-Daudé]

On 7/1/20 6:43 PM, Alex Bennée wrote:
> 
> Philippe Mathieu-Daudé <f4bug@amsat.org> writes:
> 
>> On 7/1/20 3:56 PM, Alex Bennée wrote:
>>> For some reason these tests fail all the time on GitLab. I can
>>> re-create the hang around 3% of the time locally but it doesn't seem
>>> to be MTTCG related. For now skipIf on GITLAB_CI.
>>>
>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>> Cc: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
>>> ---
>>>  tests/acceptance/machine_mips_malta.py | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/tests/acceptance/machine_mips_malta.py 
>>> b/tests/acceptance/machine_mips_malta.py
>>> index 92b4f28a112..7c9a4ee4d2d 100644
>>> --- a/tests/acceptance/machine_mips_malta.py
>>> +++ b/tests/acceptance/machine_mips_malta.py
>>> @@ -15,6 +15,7 @@ from avocado import skipUnless
>>>  from avocado_qemu import Test
>>>  from avocado_qemu import wait_for_console_pattern
>>>  from avocado.utils import archive
>>> +from avocado import skipIf
>>>  
>>>  
>>>  NUMPY_AVAILABLE = True
>>> @@ -99,6 +100,7 @@ class MaltaMachineFramebuffer(Test):
>>>          """
>>>          self.do_test_i6400_framebuffer_logo(1)
>>>  
>>
>> So the test works using a single core...
>> Good we have a test to figure the bug!
> 
> It's about a 1-3% failure rate on my big test box but hits every time on
> CI. However I did disable MTTCG and still saw failures so I think it's a
> more subtle breakage than just a straight race.

I first thought it was a MTTCG problem, but then I realized you didn't
disable the single core test. When using >1 core, the malta uses a
different device, the CPS for Coherent Processing System. It contains
a Inter-Thread Communication Unit and a Global Interrupt Controller.
There might be a I/O locking problem. In particular, some of these
devices access the &cpu->env (the ITU is more of micro-architecture).

This is why I was excited by your finding :) We might have a way
to figure it out.

> 
>>
>> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>>
>>> +    @skipIf(os.getenv('GITLAB_CI'), 'Running on GitLab')
>>>      def test_mips_malta_i6400_framebuffer_logo_7cores(self):
>>>          """
>>>          :avocado: tags=arch:mips64el
>>> @@ -108,6 +110,7 @@ class MaltaMachineFramebuffer(Test):
>>>          """
>>>          self.do_test_i6400_framebuffer_logo(7)
>>>  
>>> +    @skipIf(os.getenv('GITLAB_CI'), 'Running on GitLab')
>>>      def test_mips_malta_i6400_framebuffer_logo_8cores(self):
>>>          """
>>>          :avocado: tags=arch:mips64el
>>>
> 
>