JEP 271: Unified GC Logging - First pre-review

[Staffan Friberg]

Ah, think I got confused by the GC id being printed. I guess that is new 
in JDK 9 EA?

//Staffan

On 10/26/2015 11:13 PM, Bengt Rutisson wrote:
>
> Hi Staffan,
>
> Thanks for looking at this!
>
> On 2015-10-26 18:14, Staffan Friberg wrote:
>> Just skimmed so far, will give it a more through look.
>>
>> Do we want to keep the space after the the Times output? Does it add 
>> any value?
>> Can bite you sometimes when you grep and look for line endings.
>>
>> "[Times: user=0.10 sys=0.00 real=0.02 secs] "
>>
>
> Maybe I was unclear in my email. The logs for PrintGC and 
> PrintGCDetails are the logs for the "old" logging. In the new logging 
> the Times output looks like this:
>
> [1.165s][info   ][gc,cpu      ] GC#1 CPU Times: user=0.39s sys=0.00s 
> real=0.40s
>
> Or am I misunderstanding the question?
>
> Bengt
>
>> //Staffan
>>
>> On 10/26/2015 05:26 AM, Bengt Rutisson wrote:
>>>
>>> Hi again everyone,
>>>
>>> An update on the work for JEP 271 Unified GC Logging.
>>>
>>> I now have a working prototype that covers all GCs. Here are some 
>>> examples comparing the old format (using -XX:+PrintGC and 
>>> -XX:+PrintGCDetails) with the new format (using -Xlog):
>>>
>>> http://cr.openjdk.java.net/~brutisso/JEP-271/pre-review.00/compare.html
>>>
>>> The new logging format, using -Xlog, is much more flexible than the 
>>> old format. So, the comparison table on the above page is by no 
>>> means complete. I hope it will give a good overview, but to get a 
>>> real feel for how the new logging works I think it is necessary to 
>>> run locally and play around with the logging options.
>>>
>>> Here is a webrev of the changes so far:
>>> http://cr.openjdk.java.net/~brutisso/JEP-271/pre-review.00/webrev.00/
>>>
>>> There is still work to do and I have some known issues with the code 
>>> changes. So, I am currently not asking for too much feedback on the 
>>> actual code changes. I am more looking for feedback on the logging 
>>> behavior. The webrev can be useful to get a feel for what the code 
>>> changes will look like but mostly I think it can be used to apply 
>>> the patch and build your own HotSpot to try out the new logging.
>>>
>>> Some changes based on the initial feedback:
>>> - Start and end timestamps for the GC included on the GC log line.
>>> - Printing the unit of a value without a space. I.e. "10.345ms" 
>>> instead of "10.345 ms". (Still working on fixing this in all places 
>>> as well as trying to use milliseconds instead of seconds in as many 
>>> places as possible.)
>>> - Printing heap change information with a fixed unit. I am now using 
>>> M for overall heap transition and K for detailed information on the 
>>> debug level.
>>> - Removed the "summary" tag. Instead the end logging for a GC 
>>> includes all relevant information.
>>>
>>> All feedback is very welcome!
>>>
>>> Thanks,
>>> Bengt
>>
>