RFR: 8214712: Archive Attributes$Name.KNOWN_NAMES

Claes Redestad claes.redestad at oracle.com
Mon Dec 3 16:02:53 UTC 2018


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

Thanks!

/Claes


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