[RFR] 8064716: TestHumongousShrinkHeap.java can not be run with -XX:+ExplicitGCInvokesConcurrent

Bengt Rutisson bengt.rutisson at oracle.com
Fri Nov 14 08:46:59 UTC 2014

On 2014-11-13 19:17, Jesper Wilhelmsson wrote:
> That depends.. Will this work for all cases where 
> -XX:+ExplicitGCInvokesConcurrent is added to the command line from 
> different frameworks etc?

Jesper, the command line flags specified in the @run tag are *appened* 
to whatever the framework passes in. So, with Andrey's change the 
-XX:-ExplicitGCInvokesConcurrent in the @run tag will always override 
any -XX:+ExplicitGCInvokesConcurrent passed in from the framework. Note 
that this is a "normal" hotspot flag (not specially treated like the GC 
selection flags) so there is not conflict in specifying the same flag 
multiple times on the command line. The rule "last one wins" applies.

Andrey, the changes look good.

One minor thing is that I would prefer the @run tag in 
TestHumongousShrinkHeap.java to be a single line. I think it is a bit 
hard to read when the @run tag gets split up over multiple lines:

   30  * @run main/othervm -XX:-ExplicitGCInvokesConcurrent 
   31  * -XX:MaxHeapFreeRatio=12 -XX:+UseG1GC -XX:G1HeapRegionSize=1M 
   32  * TestHumongousShrinkHeap

Then a general question. We need this change because we some days rotate 
in -XX:+ExplicitGCInvokesConcurrent in our nightly testing. Is that 
really a good idea? (I'm sure it was requested from the GC team at some 
point, but maybe it is time to re-evaluate that decision.) A different 
way of handling these failures would be to stop rotating in that flag in 
our testing. I am not sure it really improves our quality and apparently 
it causes issues. Maybe we should just add a few tests that explicitly 
test with -XX:+ExplicitGCInvokesConcurrent?


> /Jesper
> Andrey Zakharov skrev 13/11/14 18:11:
>> Simplest way is the preferred way to solve issues, right?
>> On 13.11.2014 22:09, Jesper Wilhelmsson wrote:
>>> Hi Andrey,
>>> Is this the preferred way over using @requires?
>>> /Jesper
>>> Andrey Zakharov skrev 13/11/14 18:05:
>>>> Hi, team. Excuse me for disturbing you, here is simple fix for subj.
>>>> I've added explicit -XX:-ExplicitGCInvokesConcurrent to invocations
>>>> Its fixes at least twu test bugs:
>>>> https://bugs.openjdk.java.net/browse/JDK-8062957
>>>> https://bugs.openjdk.java.net/browse/JDK-8064716
>>>> webrev:
>>>> http://cr.openjdk.java.net/~azakharov/8064716/webrev/
>>>> Thanks.

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