Code Review - 6736316 TEST_BUG: Timeout value in java/util/concurrent/locks/Lock/FlakyMutex.java is insufficient
david.holmes at oracle.com
Wed Nov 23 06:27:53 UTC 2011
Thumbs up from me.
On 23/11/2011 1:46 AM, Gary Adams wrote:
> Revised webrev is available
> - removed the loop on termination
> - increased the original internal termination timeout
> to 120 seconds.
> The termination can exit sooner as the services are shutdown.
> The 120 second timeout is consistent with the jtreg defaults,
> but can also work standalone as a hang check.
> It may be best to engage Doug Lea with a batch of updates
> for the concurrent tests. I agree we need to keep tests in sync.
> Hopefully, the effort here for slow machine fixes will be worth while
> I think it is important to monitor unexpected slowdowns in
> the system as a whole, but there are better tools for that analysis
> in the standard performance benchmarks.
> On 11/21/11 09:08 PM, David Holmes wrote:
>> Hi Gary,
>> On 22/11/2011 5:26 AM, Gary Adams wrote:
>>> The original complaint about the flakey mutex regression test is
>>> that it was failing on slower machines. The delay at the end of
>>> the processing is unnecessarily restrictive. Since the test harness
>>> will terminate after 120 seconds if the test hangs, the test does
>>> not have to terminate more quickly.
>>> Here's a propose compromise that allows the service up to 120 seconds
>>> to terminate and allows an early exit if the service completes sooner.
>>> Alternatively, we could just increase the timeout to the full 120
>>> which will also exit sooner if the service completes earlier.
>> The loop serves no purpose. If you want to wait a maximum of 120
>> seconds then use a timeout of 120 seconds. As you said,
>> awaitTermination will return earlier if termination completes.
>> I support raising the timeout rather than waiting forever, as these
>> tests should be able to run standalone and in that case they should
>> not hang upon encountering a bug. I'm wary of assuming there is a
>> higher-level test harness involved. Also note that
>> java/util/concurrent tests are generally updated in collaboration with
>> Doug Lea as he also maintains these tests for the jsr166 repository -
>> and runs them.
>> I do have a concern that raising the timeouts/delays too high means
>> that they will no longer be of any use in detecting general unexpected
>> slowdowns. This is a delicate balance between accommodating slow
>> machines and flagging problems with unexpected slowdowns. Maybe there
>> is nothing we can do about that, but I want to flag it.
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