RFR (XS) 8152957: Improve specificity of safepoint logging to print safepoint typ

[coleen.phillimore at oracle.com]

On 12/19/17 5:14 PM, David Holmes wrote:
> On 20/12/2017 8:07 AM, coleen.phillimore at oracle.com wrote:
>> On 12/19/17 5:05 PM, David Holmes wrote:
>>> Hi Coleen,
>>>
>>> On 20/12/2017 6:12 AM, coleen.phillimore at oracle.com wrote:
>>>> Summary: upgrade safepoint begin logs to Info logging, which has 
>>>> the reason.
>>>
>>> 410   log_info(safepoint)("Entering safepoint region: %s", 
>>> VMThread::vm_safepoint_description());
>>> 497/504       log_debug(safepoint)("Leaving safepoint region");
>>>
>>> You need to change the "leaving" part to info as well.
>>
>> I had that but it seems like extra not interestesting info.  The 
>> safepoint stopped time is more useful and that's when we've left the 
>> safepoint region.
>
> Seems unbalanced to me. And it's not clear from where the "safepoint 
> stopped time" actually gets printed.

If you think it's helpful then I'll add it.  It comes from this line 
closer to the end of the function.

       RuntimeService::record_safepoint_end();

thanks,
Coleen

>>>
>>> Though I'm not clear how this simple change relates to the bug 
>>> synopsis and the request to "print safepoint type" ??
>>
>> The VMThread::vm_safepoint_description() says why we safepoint. Which 
>> is RevokeBias most of the time.
>
> Ah! Right.
>
> Thanks,
> David
>
>> thanks
>> Coleen
>>>
>>> Thanks,
>>> David
>>>
>>>> See bug for sample.
>>>>
>>>> Tested with existing jtreg tests to make sure new logging line 
>>>> doesn't break anything.
>>>>
>>>> open webrev at http://cr.openjdk.java.net/~coleenp/8152957.01/webrev
>>>> bug link https://bugs.openjdk.java.net/browse/JDK-8152957
>>>>
>>>> Thanks,
>>>> Coleen
>>