On 2018-05-03 01:29, mandy chung wrote:
On 4/30/18 5:49 AM, Claes Redestad wrote:
Hi,
please review this patch to enable caching of getCanonicalName and
getSimpleName, repeated calls of which has been reported to be a
performance
bottleneck. The caching improves performance of these methods by up
to 20x.
Rather than adding new fields to Class itself, which would have
footprint implications on classes, we can piggy-back on
Class$ReflectionData object.
Webrev: http://cr.openjdk.java.net/~redestad/8187123/open.02/
Bug: https://bugs.openjdk.java.net/browse/JDK-8187123
It's a fine idea to leverage ReflectionData to cache the names. Can
you update line 2916 for this change? For example, reflection data
caches the names and members. It will get invalidated when JVM TI
RedefineClasses is called.
Done.
newReflectionData could be updated to copy the simpleName and
canonicalName from oldReflectionData. The perf isn't a concern when
the class is being redefined. As the class name is unchanged, it
might be good to copy the names from older reflection data.
I prefer not to, as I think we should optimize for the normal cases
here, which means either a first time create or replacing a cleared
reference. In neither of these cases there's any cached data to copy
over, so we'd add code (including at least one branch) that'd never be
beneficial for the normal case. And as you say: perf probably isn't a
primary concern when classes are being redefined, so why add an
optimization that only applies to that case?
/Claes
