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

[David Holmes]

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?

Thanks,
David

> Thanks,
> Coleen