RFR for JDK-6772009 Intermittent test failure: java/util/concurrent/locks/ReentrantLock/CancelledLockLoops.java test failed with 'Completed != 2'
david.holmes at oracle.com
Thu Nov 21 02:35:24 UTC 2013
On 21/11/2013 10:28 AM, Martin Buchholz wrote:
> I again tried and failed to reproduce a failure. Even if I go whole hog
> and multiply TIMEOUT by 100 and divide ITERS by 100, the test continues to
> PASS. Is it just me?!
I think you are going the wrong way Martin - you want the timeout to be
smaller than the time it takes to execute ITERS.
> I don't think there's any reason to make result long. It's not even used
> except to inhibit hotspot optimizations.
> + private volatile long result = 17;//Can get int overflow,so using long
Further the subsequent use of += is incorrect as it is not an atomic
operation. Even if we don't care about the value, it looks bad.
I'm not sure result must be updated if we get a BrokenBarrierException
either. Probably harmless, but necessary?
> need to fix spelling and spacing below.
> + barrier.await();//If a BrokeBarrierException happens
> here(due to
There are a number of style issues with spacing around comments.
And I don't think this change is sufficient to claim co-author status
with Doug either ;-)
The additional tracing may be useful but seems stylistically different
from the rest of the code.
Overall I'm suspicious that the changed timeout actually fixes anything
- normally we need to add longer timeouts not shorter ones. Does this
fail on a range of machines or only specific ones? Have we verified that
the clocks/timers are behaving properly on those systems?
> On Wed, Nov 20, 2013 at 11:52 AM, srikalyan <
> srikalyan.chandrashekar at oracle.com> wrote:
>> Hi Martin , apologies for the delay , was trying to get help for hosting
>> my webrev. . Please see inline text.
>> On 11/19/13, 10:35 PM, Martin Buchholz wrote:
>> Hi Kalyan,
>> None of us can review your changes yet because you haven't given us a
>> URL of your webrev.
>> It is located here
>> I've tried to make the jsr166 copy of CancelledLockLoops fail by
>> adjusting ITERS and TIMEOUT radically up and down, but the test just keeps
>> on passing for me. Hints appreciated.
>> Bump up the timeout to 500ms and you will see a failure (i can see it
>> consistently on my machine Linux 64bit,8GBRAM,dual cores, with JDK 1.8
>> latest any promoted build).
>> On Tue, Nov 19, 2013 at 6:39 PM, srikalyan chandrashekar <
>> srikalyan.chandrashekar at oracle.com> wrote:
>>> Suggested Fix:
>>>> a) Decrease the timeout from 100 to 50ms which will ensure that the test
>>>> will pass even on faster machines
>> This doesn't look like a permanent fix - it just makes the failing case
>> Thats true , the other way is to make the main thread wait on TIMEOUT
>> after firing the interrupts instead of other way round, but that would be
>> over-optimization which probably is not desirable as well. The 50 ms was
>> arrived at empirically after running several 100 times on multiple
>> configurations and did not cause failures.
>> Ph: (408)-585-8040
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