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

Todd Fiala via lldb-dev lldb-dev at lists.llvm.org
Wed Sep 23 14:56:18 PDT 2015

Yeah good idea.

Anyways, that's what I'm going after.

On the Windows front, is there any reason other than lack of
timeout/gtimeout why you wouldn't want timeouts?  I'm trying to figure if
there is any reason I would want to work this in as an optional thing.
 (Making it not optional would be slightly less complicated but either way
isn't particularly a big deal).


On Wed, Sep 23, 2015 at 2:45 PM, Zachary Turner <zturner at google.com> wrote:

> No obvious reason I see why that wouldn't work.  You probably want to wrap
> the "thread 1" code in a try: ... except: pass because p.terminate probably
> will cause an exception on the other thread.
> On Wed, Sep 23, 2015 at 2:40 PM Todd Fiala <todd.fiala at gmail.com> wrote:
>> A nice bit here, also, is for those places where we are using timeout
>> (Linux, OS X, etc.) we get to trade off and use a thread where we were
>> using a whole different process.  (i.e. the timeout wrapper process goes
>> away).
>> On Wed, Sep 23, 2015 at 2:38 PM, Todd Fiala <todd.fiala at gmail.com> wrote:
>>> 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
>>>>> _______________________________________________
>>>>> lldb-dev mailing list
>>>>> lldb-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
>>> --
>>> -Todd
>> --
>> -Todd

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