[lldb-dev] Moving test runner timeout logic into Python

[Todd Fiala via lldb-dev]

Yep - the approach (for now) is likely to look like:

p = subprocess.Popen(...) # exact call differs between Windows/Non-Windows

done_event = # some kind of semaphore/event, probably
threading.Thread.Event()

spinup thread 1, running this code:
    # Thread 1 - grab output, do communicate() call
    p.communicate()
    # Signal we finished - the process ended successfully.
    done_event.signal()

# ...back to the thread that called subprocess.Popen()

# Wait for time timeout value for the inferior dotest.py process to
complete..
timed_out = done_event.wait(timeout_in_seconds)

# If timed_out indicates the timeout occurred, we timed out.
# And thus, the process did not finish on time.
if timed_out == True:
   # Kill the inferior dotest
   p.kill() # or p.terminate()
   # This will cause the other thread to fall through now, but we know it
timed out.
   # Could get fancier here and do a nice kill, then a less blockable
kill.  But make the
   # process die one way or another.

# do the other post-process activity here...



^= that's rough pseudo-code.  I need to look up a few details.  But that's
more or less what I was thinking.  Looked like all of that was available on
Windows.  We can also have it only optionally time out.

Something like that is what I had in mind.

On Wed, Sep 23, 2015 at 2:28 PM, Zachary Turner <zturner at google.com> wrote:

> Can you offer a hint about how you plan to implement this?  When you say
> it we should get the same behavior everywhere, I assume this means Windows
> too, which currently does not support running with a timeout at all
> (because timeout / gtimeout aren't present)
>
> On Wed, Sep 23, 2015 at 2:22 PM Todd Fiala via lldb-dev <
> lldb-dev at lists.llvm.org> wrote:
>
>> Hi all,
>>
>> Over the last two days, I've hit some inconsistencies across platforms
>> surrounding signal handling and the operation of the timeout/gtimeout
>> executable mechanism that we use to handle timeouts of tests.  The net
>> result is I still see tests sometimes hang up the test running process,
>> even though my changes in the last couple days seem to have reduced the
>> frequency somewhat.
>>
>> I'd like to address that once and for all with something that is less
>> likely to differ across platforms.  I have a relatively simple way to do
>> that within the parallel test runner directly.  I'm planning on prototyping
>> that now, but before I dive too far into that, I wanted to expose the idea
>> in case somebody had any major concerns with not using timeout/gtimeout on
>> the systems that had it.
>>
>> I expect it to be a relatively small change when I get it up for review.
>>
>> The nice thing about going straight-python on it is we should get the
>> same behavior everywhere, and not depend on signal handling to do it.
>>
>> Thoughts?
>> --
>> -Todd
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>> lldb-dev at lists.llvm.org
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>>
>


-- 
-Todd
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