RFR: 8141211: Convert TraceExceptions to Unified Logging

[Bengt Rutisson]

On 2015-12-16 22:43, Coleen Phillimore wrote:
>
>
> On 12/16/15 4:01 PM, John Rose wrote:
>> On Dec 15, 2015, at 12:26 PM, Rachel Protacio 
>> <rachel.protacio at oracle.com> wrote:
>>> - each incident of ttyLocker that involved separate logging lines 
>>> for the same message have been consolidated to one line
>>> - each incident of ttyLocker that involved separate print statements 
>>> to one logging line has been changed to write to a buffer first, 
>>> then print the entire line at once to the log stream
>> This is a strong argument for putting such functionality into the UL 
>> framework,
>> instead of giving developers the unfortunate choice of either (a) 
>> doing it right
>> with a bunch of random logic (Rachel's choice here) or (b) sweeping 
>> it under
>> the carpet by breaking up a multi-part message into several log 
>> messages.
>>
>> We need to admit this is the Achilles Heel of logging as normally 
>> conceived
>> (especially for very long multi-part messages like disassembler output,
>> backtraces, or compilation logs), and just fix it in the UL frameowrk.
>
> Yes, I agree.  We should file a high priority RFE against UL for this 
> if one isn't filed already.  The runtime only uses ttyLocker (as far 
> as I found) for TraceExceptions but the compiler uses it more often to 
> aggregate messages.   The lack of a locking mechanism seems to be one 
> of the factors blocking the compiler group adoption of this feature.   
> And will block more complex runtime logging conversions.
>
> So what do people vote that we do?  Should we log the messages 
> separately until this is fixed?  I agreed with making these logs one 
> line because even though they wrap, they weren't that long. It would 
> be nice to be able to do the conversion work to UL concurrently while 
> finding problems in the framework, and not be stuck.

 From my point of view it would be very unfortunate to require all 
logging to take an extra lock. If the multiline support can be 
implemented in the UL framework without any extra cost for "normal" 
logging I would be fine with it. But if it would slow down the normal 
logging, which I assume would be the case if we require an extra lock, 
then I would prefer to push the responsibility up to the users of the UL 
framework to synchronize properly.

Bengt

>
> Thanks,
> Coleen
>>
>> — John
>