RFR (S) 8236901: 8232759 missed a test case

[coleen.phillimore at oracle.com]

On 1/13/20 7:36 PM, David Holmes wrote:
> Hi Coleen,
>
> On 14/01/2020 7:08 am, coleen.phillimore at oracle.com wrote:
>> Summary: Use jcmd GC.class-histogram because it also works for 
>> verifying that the classes are loaded.
>
> I'm looking at GC.class_stats and GC.class_histogram output and the 
> actual test and I'm not sure the test was even working the way it was 
> expected before. If I run the test using GC.class_stats I see:
>
> ----------System.out:(20/1962)----------
> sizeof(DefineClass.class) == 8905
> class test.DefineClass
> WARNING: Ran out of C-heap; undercounted 342 total instances in data 
> below
>  1447    46         0        544           0    6752          12 
> 1351      4048    3616    8088   11704 test.DefineClass
>  1448    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1449    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1450    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1451    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1452    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1453    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1454    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1455    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1456    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
>  1457    46         0        544           0    4072          12 
> 1351      4048    3536    5488    9024 test.DefineClass
> Should have 2 DefineClass instances and we have: 11

I think the test wants *at least* 2 DefineClasses in these places, where 
it passes false to getClassStats.
>
> then
>
> System.gc()
> WARNING: Ran out of C-heap; undercounted 342 total instances in data 
> below
>  1598    47         0        544           0    6752          12 
> 1351      4048    3616    8088    11704 test.DefineClass
>  1599    47         0        544           0    4072          12 
> 1351      4048    3536    5488     9024 test.DefineClass
> Should have 2 DefineClass instances and we have: 2
>
> so the test "passes". But if I then change the test to use 
> GC.class_histogram as suggested it fails!
>
>
> ----------System.out:(7/321)----------
> sizeof(DefineClass.class) == 8909
> class test.DefineClass
> WARNING: Ran out of C-heap; undercounted 342 total instances in data 
> below
> Should have 2 DefineClass instances and we have: 0
> System.gc()
> WARNING: Ran out of C-heap; undercounted 342 total instances in data 
> below
> Should have 2 DefineClass instances and we have: 0
>

I don't know why it fails for you.  How did you run it?  Did you test my 
patch?

Coleen

> This is on a JDK where GC.class_stats still exists.
>
> David
>
>> open webrev at 
>> http://cr.openjdk.java.net/~coleenp/2020/8236901.01/webrev
>> bug link https://bugs.openjdk.java.net/browse/JDK-8236901
>>
>> Ran tier1 which runs the test on all Oracle platforms.
>>
>> Thanks,
>> Coleen