RFR: 8040935: -XX:+AggressiveOpts broken: GC triggered before VM initialization completed on several tests

Stefan Johansson stefan.johansson at oracle.com
Thu Jan 15 14:12:44 UTC 2015


On 2015-01-15 00:49, Stefan Johansson wrote:
> Hi Kim,
>
> On 2015-01-14 19:13, Kim Barrett wrote:
>> On Jan 12, 2015, at 5:01 AM, Stefan Johansson 
>> <stefan.johansson at oracle.com> wrote:
>>> Please review this testfix to avoid the following issue:
>>> https://bugs.openjdk.java.net/browse/JDK-8040935
>>>
>>> Webrev:
>>> http://cr.openjdk.java.net/~sjohanss/8040935/hotspot.00
>>>
>>> Summary:
>>> Making the test a driver test to avoid dealing with externally 
>>> specified flags. One problematic flag is AggressiveOpts, it causes 
>>> the VM to allocate more stuff during startup and that together with 
>>> UseNUMA the eden space gets to little to handle all startup 
>>> allocations. This will in turn lead to a GC being triggered before 
>>> initialization is finished, and because of that failing the test.
>>>
>>> Testing:
>>> * Tested via JPRT
>> test/gc/TestNUMAPageSize.java
>> Summary: Changed test to not be affected by external options.
>>
>> I'm not sure I like this approach to resolving the bug.  I think it
>> results in many potentially interesting configurations never being
>> tested, e.g. this tests with one and only one GC, the default GC.  It
>> ignores the nightly build cycling through various configurations to
>> increase test coverage.
>>
> Thanks for taking a look at this. I see your point and think we should 
> do something better. The test was originally written to test a 
> specific regression we had when starting with -Xmx8m and -XX:+UseNUMA 
> with the default collector, but that doesn't mean we shouldn't test it 
> for the others as well. I'm not sure if we have any NUMA support for 
> the other collectors today, but no harm in testing that the option 
> doesn't cause any problems.
>
> I see two ways of improving the coverage, one would be to use 
> @requires to say that AggressiveOpts can't be true, but that will 
> still leave the possibility to set other options that might push us 
> over the limit of allocations during startup. The other way would be 
> to extend the test to run with all collectors explicitly, but ignore 
> any options passed in. This would of course still have less coverage 
> than today, but at least all collectors would be covered.
>
> I would prefer the second one, it would be robust and the coverage 
> would be ok.
>

Updated webrev that tests all GCs:
http://cr.openjdk.java.net/~sjohanss/8040935/hotspot.01/

Verified that the test still passes when run through JPRT.

Thanks,
Stefan

> Thanks,
> Stefan
>



More information about the hotspot-gc-dev mailing list