RFR (S) 8153413: Exceptions::_throw always logs exceptions, penalizing performance

[coleen.phillimore at oracle.com]

On 2/19/19 9:32 PM, David Holmes wrote:
> Hi Coleen,
>
> Looks good! One comment/suggestion below.
>
> On 20/02/2019 6:41 am, coleen.phillimore at oracle.com wrote:
>> Summary: construct exception string into Event message directly.
>>
>> This is somewhat of a minimal change that has a small benefit to 
>> performance (see bug for more details).  It's been merged with 
>> Yasumasa's change.
>>
>> Tested with hs-tier1-2 and performance tests.
>>
>> open webrev at 
>> http://cr.openjdk.java.net/~coleenp/2019/8153413.01/webrev
>> bug link https://bugs.openjdk.java.net/browse/JDK-8153413
>
> src/hotspot/share/utilities/events.cpp
>
> +   double timestamp = fetch_timestamp();
> +   MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
>
> Might it be better to get the timestamp after you have the lock?

All the other events grab the timestamp first, so I want to leave this 
one also.
Thanks,
Coleen

>
> Thanks,
> David
>
>> Thanks,
>> Coleen