RFR(S) 8028595 : WhiteBox API for stress testing of TieredCompilation

[Vladimir Kozlov]

On 12/8/14 3:05 PM, Igor Ignatyev wrote:
> On 12/09/2014 01:55 AM, Vladimir Kozlov wrote:
>> On 12/8/14 11:58 AM, Igor Ignatyev wrote:
>>> Vladimir,
>>>
>>> http://cr.openjdk.java.net/~iignatyev/8028595/hotspot/webrev.01/
>>>
>>> On 12/03/2014 12:54 AM, Vladimir Kozlov wrote:
>>>> On 12/2/14 1:32 AM, Igor Ignatyev wrote:
>>>>> Vladimir,
>>>>>
>>>>> I need Unsafe.getCompiler for DeoptimizeFramesTest, because in
>>>>> 'non-makeNotEntrant' case, there's no way to determine if the method
>>>>> was
>>>>> deoptimized.
>>>>
>>>> I don't understand how you check that in the test.
>>> getCompiler returns 0 if method isn't compiled or (in my case) was
>>> deoptimized. TestCaseImpl::method uses 'getCompiler' method as a
>>> multiplier for result value. if TestCaseImpl::method returns 0, for-loop
>>> (lines 75--80) quits.
>>
>> Okay. I missed that compile() calls method() and returns sum of its
>> results.
>>
>>>
>>>>
>>>> If you only want to check if method was deoptimized you can check
>>>> MethodData::decompile_count().
>>>
>>> MethodData::decompile_count is incremented only if nmethod is compiled
>>> by c2. so it can't be used.
>>>>
>>>> I don't like extending Unsafe API for just this test.
>>> well, I can move it to whitebox, if you don't mind to have intrinsics
>>> for it.
>>
>> I would rather see changes in nmethod and new WB accessors to it.
>>
>> And sorry, I don't like the test. The test does not have
>> comments/description. It is difficult to judge, is it doing what it is
>> suppose to do or not.
> yeap, sorry. I'll add the comments.
>
>>
>> nm->make_not_entrant() will call method()->clear_code(). So how you
>> expect that checkCompiled() will not throw Error after deoptimization?:
>>
>>    69         WHITE_BOX.deoptimizeFrames(makeNotEntrant);
>>    70         checkCompiled();
>>
>> Your loop (lines 75--80) is in a race of compilations vs
>> deoptimizations. The test on machines with different numbers of threads
>> will behave differently. Where is guarantee that you will get your
>> result == 0 case?
>> Why do you even need these *concurrent* deoptimization, compilation
>> loops?
>> Can you do it synchronously? Execute method in separate thread and stop
>> it when you get compilation of requested level or other condition
>> (recursion level). Do deoptimization in main thread and see if methods
>> are deoptimized.
>
> WB::deoptimizeFrames has to deoptimize methods which are currently on
> stack, that's why I expect that checkCompiled on line 70 won't throw an
> exception and that's why I do need these concurrent
> deoptimization/compilation.

So you are testing in first lines that if the compiled method does not 
have the frame on stack it will not be deoptimized - *comment* please.

Again. I think the test will be simpler if you execute compiled method 
in a separate thread instead of main where you do all checks.

Vladimir

>
>>
>> Regards,
>> Vladimir
>>
>>>
>>>>
>>>> Thanks,
>>>> Vladimir
>>>>
>>>>>
>>>>> Thanks,
>>>>> Igor
>>>>>
>>>>> On 12/02/2014 04:54 AM, Vladimir Kozlov wrote:
>>>>>> Why you need new Unsafe.getCompiler()?
>>>>>>
>>>>>> thanks,
>>>>>> Vladimir
>>>>>>
>>>>>> On 11/27/14 2:14 PM, Igor Ignatyev wrote:
>>>>>>> http://cr.openjdk.java.net/~iignatyev/8028595/hotspot/webrev.00/
>>>>>>> 220 lines changed: 212 ins; 8 del; 0 mod;
>>>>>>>
>>>>>>> http://cr.openjdk.java.net/~iignatyev/8028595/jdk/webrev.00/
>>>>>>> 4 lines changed: 4 ins; 0 del; 0 mod;
>>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> please review the patch which adds
>>>>>>>   - a new whitebox method 'deoptimizeFrames' which deoptimizes
>>>>>>> methods
>>>>>>> which are currently on stack
>>>>>>>   - Unsafe.getCompiler methodhotspot-compiler-dev at openjdk.java.net
>>>>>>> which
>>>>>>> returns 0, 1, 2 if it is interpreted, compiled by c1, c2
>>>>>>> accordingly.
>>>>>>>
>>>>>>> jbs: https://bugs.openjdk.java.net/browse/JDK-8028595
>>>>>>> testing: jprt + new added test
>>>>>>>
>>>
>