RFR(S): 8246493: JDI stress/serial/mixed002 needs to use WhiteBox.deflateIdleMonitors support

Chris Plummer chris.plummer at oracle.com
Mon Jun 29 21:02:37 UTC 2020 

Ok, in that case it sounds best not to backport. It would be best to 
make this clear in the bug so there is no future attempt to backport 
this change except to versions that have already done the 
WhiteBox.deflateIdleMonitors() backport.

thanks,

Chris

On 6/29/20 1:53 PM, Daniel D. Daugherty wrote:
> The WhiteBox.deflateIdleMonitors() support is not in JDK15. That's
> something that added in JDK16 so I'd have to also backport that support.
> That support was included with another change (getting rid of the special
> deflation request mechanism) that is not appropriate for JDK15.
>
> Short version: I don't think we want to back port part of a patch from
> JDK16 -> JDK15 in order to fix this test bug.
>
> Dan
>
>
> On 6/29/20 4:41 PM, Chris Plummer wrote:
>> Hi Dan,
>>
>> I think you should push it directly to 15 since it's a new issue.
>>
>> thanks,
>>
>> Chris
>>
>> On 6/29/20 12:53 PM, Daniel D. Daugherty wrote:
>>> Chris,
>>>
>>> Thanks. One last thing... since this is a test bug, I wasn't 
>>> planning to
>>> backport the fix to JDK15. The test is ProblemListed there so we 
>>> won't see
>>> the intermittent failures.
>>>
>>> Are you and Serguei good with not fixing this test bug in JDK15?
>>>
>>> Dan
>>>
>>> P.S.
>>> Thanks again for your sleuthing that linked the bug to my
>>> fix for JDK-8153224.
>>>
>>>
>>> On 6/29/20 3:49 PM, Chris Plummer wrote:
>>>> Looks good.
>>>>
>>>> Chris
>>>>
>>>> On 6/29/20 12:45 PM, Daniel D. Daugherty wrote:
>>>>> Chris and Serguei,
>>>>>
>>>>> Thanks for the fast reviews!!
>>>>>
>>>>> I generated the webrev in my "mach5" directory and that was baselined
>>>>> on the jdk-16+3 snapshot and that doesn't include the ProblemList 
>>>>> change.
>>>>> Sigh...  I have updated the repo to "current" and regenerated the 
>>>>> webrev.
>>>>>
>>>>> test/hotspot/jtreg/ProblemList.txt  now shows:
>>>>>
>>>>> @@ -126,11 +126,10 @@
>>>>>  vmTestbase/nsk/monitoring/ThreadMXBean/ThreadInfo/Deadlock/JavaDeadlock001/TestDescription.java 
>>>>> 8060733 generic-all
>>>>>
>>>>>  vmTestbase/nsk/jdi/ThreadReference/stop/stop001/TestDescription.java 
>>>>> 7034630 generic-all
>>>>>  vmTestbase/nsk/jdi/VirtualMachine/redefineClasses/redefineclasses021/TestDescription.java 
>>>>> 8065773 generic-all
>>>>>  vmTestbase/nsk/jdi/VirtualMachine/redefineClasses/redefineclasses023/TestDescription.java 
>>>>> 8065773 generic-all
>>>>> -vmTestbase/nsk/jdi/stress/serial/mixed002/TestDescription.java 
>>>>> 8246493 generic-all
>>>>>
>>>>>  vmTestbase/nsk/jdb/eval/eval001/eval001.java 8221503 generic-all
>>>>>
>>>>>  vmTestbase/metaspace/gc/firstGC_10m/TestDescription.java 8208250 
>>>>> generic-all
>>>>>  vmTestbase/metaspace/gc/firstGC_50m/TestDescription.java 8208250 
>>>>> generic-all
>>>>>
>>>>> Thanks again for the fast reviews!!
>>>>>
>>>>> Dan
>>>>>
>>>>>
>>>>> On 6/29/20 3:41 PM, serguei.spitsyn at oracle.com wrote:
>>>>>> Hi Dan,
>>>>>>
>>>>>> The same as from Chris.
>>>>>> The ProblemList.txt has no changes.
>>>>>> Otherwise, it looks good.
>>>>>>
>>>>>> Thanks,
>>>>>> Serguei
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 6/29/20 12:37, Chris Plummer wrote:
>>>>>>> Hi Dan,
>>>>>>>
>>>>>>> Something is wrong with ProblemList.txt. It doesn't show any 
>>>>>>> changes, but I also don't see mixed002 in the file anymore.
>>>>>>>
>>>>>>> Otherwise the changes look good.
>>>>>>>
>>>>>>> thanks,
>>>>>>>
>>>>>>> Chris
>>>>>>>
>>>>>>> On 6/29/20 12:21 PM, Daniel D. Daugherty wrote:
>>>>>>>> Greetings,
>>>>>>>>
>>>>>>>> I have a fix for the following bug:
>>>>>>>>
>>>>>>>>     JDK-8246493 JDI stress/serial/mixed002 needs to use 
>>>>>>>> WhiteBox.deflateIdleMonitors support
>>>>>>>>     https://bugs.openjdk.java.net/browse/JDK-8246493
>>>>>>>>
>>>>>>>> Here's the webrev URL:
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~dcubed/8246493-webrev/0_for_jdk16/
>>>>>>>>
>>>>>>>> The test bug that's being fixed:
>>>>>>>>
>>>>>>>> vmTestbase/nsk/jdi/stress/serial/mixed002/TestDescription.java 
>>>>>>>> fails
>>>>>>>>     intermittently with the following message:
>>>>>>>>
>>>>>>>>      nsk.share.TestBug: There are more than one(2) instance of 
>>>>>>>> 'nsk.share.jpda.StateTestThread in debuggee
>>>>>>>>
>>>>>>>> Summary of the fix:
>>>>>>>>
>>>>>>>>     Use WhiteBox.deflateIdleMonitors() to make sure that all 
>>>>>>>> inflated
>>>>>>>>     ObjectMonitors are deflated after each debuggee has been run.
>>>>>>>>
>>>>>>>> This fix has been tested with a Mach5 Tier5 test run that 
>>>>>>>> executes all
>>>>>>>> of the JDI tests (along with JDWP, JVM/TI and other 
>>>>>>>> Serviceability tests).
>>>>>>>> I also did five 100 iteration runs of the failing mix002 test. 
>>>>>>>> Each Mach5
>>>>>>>> job set ran the test 100 times on Linux-X64, macOSX, and 
>>>>>>>> Win-X64 for a
>>>>>>>> total of (5 * 100 * 3) iterations of 
>>>>>>>> nsk/jdi/stress/serial/mixed002. There
>>>>>>>> were no failures.
>>>>>>>>
>>>>>>>> Thanks, in advance, for any comments, questions or suggestions.
>>>>>>>>
>>>>>>>> Dan
>>>>>>>>
>>>>>>>>
>>>>>>>> Gory details:
>>>>>>>>
>>>>>>>> The primary focus of the fix is in the first three files in the 
>>>>>>>> webrev:
>>>>>>>>
>>>>>>>> test/hotspot/jtreg/vmTestbase/nsk/share/jdi/SerialExecutionDebuggee.java 
>>>>>>>>
>>>>>>>> test/hotspot/jtreg/vmTestbase/nsk/jdi/stress/serial/mixed002/TestDescription.java 
>>>>>>>>
>>>>>>>> test/hotspot/jtreg/ProblemList.txt
>>>>>>>>
>>>>>>>> nsk.share.jdi.SerialExecutionDebuggee is the class that used to 
>>>>>>>> serially
>>>>>>>> execute the debuggee portion of a specific list of tests. After 
>>>>>>>> this class
>>>>>>>> is done executing a debuggee class, it needs to deflate idle 
>>>>>>>> monitors in
>>>>>>>> order to prevent a StateTestThread object created by one 
>>>>>>>> debuggee class
>>>>>>>> from confusing the next debuggee class. Each of the debuggee 
>>>>>>>> classes that
>>>>>>>> use StateTestThread expect there to be only one of these 
>>>>>>>> objects. However,
>>>>>>>> since we are running multiple debuggee classes serially *in the 
>>>>>>>> same VM*,
>>>>>>>> the StateTestThread object created in one debuggee can still be 
>>>>>>>> around
>>>>>>>> when the next debuggee runs.
>>>>>>>>
>>>>>>>> The COMMAND_CLEAR_DEBUGGEE implementation clears the 
>>>>>>>> currentDebuggee variable
>>>>>>>> which permits the debuggee to be GC'ed and is modified by this 
>>>>>>>> fix to call
>>>>>>>> WhiteBox.deflateIdleMonitors() to make sure that all inflated 
>>>>>>>> ObjectMonitors
>>>>>>>> are deflated after each debuggee has been run. This takes care 
>>>>>>>> of any pinned
>>>>>>>> StateTestThread objects (and any other inflated ObjectMonitors).
>>>>>>>>
>>>>>>>>
>>>>>>>> vmTestbase/nsk/jdi/stress/serial/mixed002 is a wrapper style 
>>>>>>>> stress test that
>>>>>>>> executes the debugger and debuggee parts of a specific list of 
>>>>>>>> tests serially
>>>>>>>> *in the same VM*. Several of the tests executed by mixed002 
>>>>>>>> make use of the
>>>>>>>> StateTestThread class. The failure is intermittent because the 
>>>>>>>> order of test
>>>>>>>> execution is shuffled automatically and sometimes the 
>>>>>>>> ServiceThread manages
>>>>>>>> to execute deflation at the right time to prevent more than one 
>>>>>>>> StateTestThread
>>>>>>>> object from existing at the same time.
>>>>>>>>
>>>>>>>> The additions to vmTestbase/nsk/jdi/stress/serial/mixed002 are 
>>>>>>>> the standard
>>>>>>>> boilerplate needed to call WhiteBox functions from test code. 
>>>>>>>> The actual call
>>>>>>>> to WhiteBox.deflateIdleMonitors() is made in 
>>>>>>>> SerialExecutionDebuggee. I did
>>>>>>>> attempt a fix where I modified the StateTestThread class to 
>>>>>>>> make the call to
>>>>>>>> WhiteBox.deflateIdleMonitors() after the internal waitOnObject 
>>>>>>>> is no longer
>>>>>>>> contended or waited on. That fix reduced the frequency of the 
>>>>>>>> failures by
>>>>>>>> about half, but it didn't solve the test bug entirely. So I had 
>>>>>>>> to make the
>>>>>>>> fix in SerialExecutionDebuggee instead.
>>>>>>>>
>>>>>>>>
>>>>>>>> test/hotspot/jtreg/ProblemList.txt is modified to re-enable the 
>>>>>>>> mix002 test.
>>>>>>>>
>>>>>>>>
>>>>>>>> The remaining nine files are also wrapper style stress tests 
>>>>>>>> that execute
>>>>>>>> the debugger and debuggee parts of a specific list of tests 
>>>>>>>> serially *in
>>>>>>>> the same VM*. Because these tests also use 
>>>>>>>> SerialExecutionDebuggee, they
>>>>>>>> also need the boilerplate changes so that 
>>>>>>>> WhiteBox.deflateIdleMonitors()
>>>>>>>> can be called.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
>

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