On 03/12/2018 16:02, Claes Redestad wrote:
Hi,
initializing java.util.jar.Attributes.Name.<clinit> executes ~20k bytecodes setting up and eagerly calculating case-insensitive hash codes for a slew of Name objects.
By archiving the resulting set of Names and initializing public constants from the archived map, we reduce time spent starting up (Name.<clinit> drops to 368 executed bytecodes) and improve the footprint sharing effect of using CDS:
http://cr.openjdk.java.net/~redestad/8214712/jdk.00/
Testing: tier1-2 running
Verified a 1-2.5ms startup improvement on java -jar Hello.jar - significant and stable reduction in instruction count, branches and branch misses - only adds ~1.1Kb to the dumped CDS archive This looks okay to me but the changes remind me that there are several attributes name in KNOWN_NAMES are should probably be removed as they aren't defined by Java SE or the JDK.
-Alan