RFR: 8196340: (coll) Examine overriding inherited methods in ArrayList and ArrayList.SubList

[Martin Buchholz]

Yet another microbenchmark coming your way.  Embarrassing to have COWAL win
all these so handily.

--- IteratorMicroBenchmark.java 11 May 2018 18:19:10 -0000 1.45
+++ IteratorMicroBenchmark.java 11 May 2018 22:35:32 -0000 1.46
@@ -564,6 +564,12 @@
                         sum[0] = 0;
                         x.replaceAll(sneakyAdder);
                         check.sum(sum[0]);}}},
+            new Job(klazz + " equals") {
+                public void work() throws Throwable {
+                    ArrayList<Integer> copy = new ArrayList<>(x);
+                    for (int i = 0; i < iterations; i++) {
+                        if (!x.equals(copy))
+                            throw new AssertionError();}}},
             new Job(klazz + " hashCode") {
                 public void work() throws Throwable {
                     int hashCode = Arrays.hashCode(x.toArray());


C2:
Method                              Millis Ratio
ArrayList equals                        58 1.000
ArrayList$SubList equals                72 1.240
LinkedList equals                      101 1.739
AbstractList$SubList equals            164 2.822
Vector equals                          162 2.790
SynchronizedRandomAccessList equals    182 3.129
CopyOnWriteArrayList equals             22 0.394
COWSubList equals                       19 0.336

C1:
Method                              Millis Ratio
ArrayList equals                       300 1.000
ArrayList$SubList equals               389 1.297
LinkedList equals                      328 1.094
AbstractList$SubList equals            349 1.162
Vector equals                          263 0.876
SynchronizedRandomAccessList equals    395 1.314
CopyOnWriteArrayList equals             78 0.262
COWSubList equals                       80 0.269