RFR: 8214712: Archive Attributes$Name.KNOWN_NAMES

Alan Bateman Alan.Bateman at oracle.com
Mon Dec 3 16:06:59 UTC 2018

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.


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