RFR: 8139564: Convert TraceDefaultMethods to Unified Logging

[Coleen Phillimore]

Hi,

I added the serviceability group so they can comment on this as well.   
I think having logging in the PRODUCT build is requested so that we can 
more easily debug customer problems.   That said, we will not enable 
logging in product if we see any performance problem.  Also for some 
options it's possible that these are strictly internal debugging options 
and in that case we'll either remove them if they're no longer useful, 
or make them Develop level options.

Printing default methods seems to be something that might be borderline 
in the second case, but we've decided to make it product level 
logging.   We could change our minds about this though, so your comments 
are welcome.

Thanks,
Coleen

On 10/15/15 6:33 PM, Ioi Lam wrote:
>
>
> On 10/15/15 10:51 AM, Rachel Protacio wrote:
>> Hi, Ioi,
>>
>> Thanks for the comments. While all valid points, the decision by the 
>> serviceability team with regards to the logging framework as a whole 
>> is to move all the output to product mode. Because of this, I ran 
>> performance tests to make sure that the newly-introduced product code 
>> will not slow it down. So yes, all the "#ifndef PRODUCT" sections 
>> that are necessary for this logging have been liberated to product mode.
>>
> Thanks Rachel. This makes sense.
>
> - Ioi
>
>> Also, I realized I did not remove the TraceDefaultMethods flag from 
>> globals.hpp, so here is the link to the updated webrev: 
>> http://cr.openjdk.java.net/~rprotacio/8139564.01/
>> Which builds appropriately. The change now encompasses all the 
>> references to TraceDefaultMethods. A compatibility request has been 
>> accepted with regards to this change.
>>
>> Thanks,
>> Rachel
>>
>> On 10/14/2015 11:58 PM, Ioi Lam wrote:
>>> Hi Rachel,
>>>
>>> Before your changes, this block of code  would be excluded from 
>>> product builds:
>>>
>>>  684 #ifndef PRODUCT
>>>  685   if (TraceDefaultMethods) {
>>>  686     tty->print_cr("Slots that need filling:");
>>>  687     streamIndentor si(tty);
>>>  688     for (int i = 0; i < slots->length(); ++i) {
>>>  689       tty->indent();
>>>  690       slots->at(i)->print_on(tty);
>>>  691       tty->cr();
>>>  692     }
>>>  693   }
>>>  694 #endif // ndef PRODUCT
>>>
>>> but after your change, it will be included in product builds. This 
>>> means product builds will have more verbose output than before. It 
>>> also means that the product builds will get bigger (because some 
>>> printing code, such as EmptyVtableSlot::print_on(), would need to be 
>>> enabled for product builds as well).
>>>
>>> I am not very familiar with UL so maybe this is an FAQ ... while 
>>> doing the UL conversion, should we add all the old "ifndef PRODUCT" 
>>> logs into the product build?
>>>
>>> Thanks
>>> - Ioi
>>>
>>> On 10/14/15 7:10 PM, Rachel Protacio wrote:
>>>> Hello! Please take a look at my enhancement, the first of the 
>>>> runtime logging flags to be converted.
>>>>
>>>> Summary: The former -XX:+TraceDefaultMethods flag is updated to the 
>>>> unified logging framework and is now replaced with 
>>>> -Xlog:defaultmethods.
>>>>
>>>> open webrev: http://cr.openjdk.java.net/~rprotacio/8139564/
>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8139564
>>>> testing: Passes JPRT, RBT, and RefWorkload performance testing.
>>>>
>>>> Thank you,
>>>> Rachel
>>>
>>
>