RFR: 8214712: Archive Attributes$Name.KNOWN_NAMES

[Claes Redestad]

Hi,

this RFE was stalled due an interaction with SA that has since been
resolved. As it still applies cleanly I'll consider it reviewed. I'm
just going to do some sanity testing (tier1) before push.

Thanks!

/Claes

On 2018-12-03 17:02, 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
> 
> Thanks!
> 
> /Claes