RFR: 8178889: Move creation of AbstractChronology comparators to call sites

[Roger Riggs]

Hi Claes,

Looks fine

Roger

On 4/18/2017 8:28 AM, Claes Redestad wrote:
> Hi,
>
> in AbstractChronology we define a number of comparators which could be 
> moved to their
> respective call site and thus be lazily initialized when needed with 
> no performance
> penalty.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8178889
> Webrev: http://cr.openjdk.java.net/~redestad/8178889/jdk.01/
>
> Testing/analysis:
> - naive micro to show this doesn't cause a regression in steady 
> state[1], for those in
> doubt
> - reduces executed bytecode by ~127K and drops 5 generated classes 
> from startup of
> applications that depend on AbstractChronology but don't use any of 
> these comparators
> - pass all java/time tests
>
> Thanks!
>
> /Claes
>
> [1]
> package org.openjdk;
> import org.openjdk.jmh.annotations.Benchmark;
> import java.time.chrono.*;
> import java.lang.reflect.*;
>
> public class ChronoComparatorBench {
>
>     public static Method timeLineOrder;
>
>     static {
>         try {
>             timeLineOrder = 
> ChronoLocalDate.class.getDeclaredMethod("timeLineOrder");
>         } catch (Exception e) {
>             throw new RuntimeException(e);
>         }
>     }
>
>     @Benchmark
>     public Object getComparator() throws Exception {
>         return timeLineOrder.invoke(null);
>     }
> }
>
> -f 1 -tu us -bm avgt
>
> Benchmark                            Mode  Cnt  Score   Error Units
> ChronoComparatorBench.getComparator  avgt   20 5.979 ± 0.067 ns/op  # 
> before
> ChronoComparatorBench.getComparator  avgt   20 5.975 ± 0.054 ns/op  # 
> after