RFR (XS) 8220688: [TESTBUG] runtime/NMT/MallocStressTest.java timed out

[David Holmes]

Hi Coleen,

This is fine to push, but some discussion below ...

On 21/05/2019 6:50 am, coleen.phillimore at oracle.com wrote:
> Summary: reduce number of threads and iterate rather than sleep.

Reducing the load of this test may be reasonable ... though perhaps it 
should be configured based on available CPUs rather than fixed numbers 
(just a thought).

But this test rarely times out (and some failures of the test have been 
incorrectly attributed with this bug - the 10 second attach timeout is 
not at all the same issue as timing out after 1h25m!), so your testing 
is unlikely to have encountered the conditions in which the timeout 
actually manifests. The test normally runs in a few minutes on linux so 
the 1h25m timeout is extreme and seems unlikely to be due simply to the 
load the test produces. So I would not be surprised if we continue to 
see occasional timeouts.

Further, the huge variation in execution time for this test across 
different platforms e.g. macOS takes 45 minutes!, suggests there may be 
something else at play here.

Thanks,
David

> Ran test 20x without timeout and faster now.  Left /timeout in test 
> because it doesn't hurt.
> 
> open webrev at http://cr.openjdk.java.net/~coleenp/2019/8220688.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8220688
> 
> Thanks,
> Coleen