RFR: 8247532: Records deserialization is slow

[Peter Levart]

Hi,


When re-running the benchmark [1] with different lengths of serialized 
arrays of records, I found that, compared to classical classes, lookup 
into the cache of adapted method handles starts to show when the length 
of array is larger (# of instances of same record type deserialized in 
single stream). Each record deserialized must lookup the method handle 
in a ConcurrentHashMap:


Benchmark                                    (length)  Mode  Cnt    Score   Error  Units
RecordSerializationBench.deserializeClasses        10  avgt   10    8.088 ± 0.013  us/op
RecordSerializationBench.deserializeClasses       100  avgt   10   32.171 ± 0.324  us/op
RecordSerializationBench.deserializeClasses      1000  avgt   10  279.762 ± 3.072  us/op
RecordSerializationBench.deserializeRecords        10  avgt   10    9.011 ± 0.027  us/op
RecordSerializationBench.deserializeRecords       100  avgt   10   33.206 ± 0.514  us/op
RecordSerializationBench.deserializeRecords      1000  avgt   10  325.137 ± 0.969  us/op


...so keeping the correctly shaped adapted method handle in the 
per-serialization-session ObjectStreamClass instance [2] starts to make 
sense:


Benchmark                                    (length)  Mode  Cnt    Score   Error  Units
RecordSerializationBench.deserializeClasses        10  avgt   10    8.681 ± 0.155  us/op
RecordSerializationBench.deserializeClasses       100  avgt   10   32.496 ± 0.087  us/op
RecordSerializationBench.deserializeClasses      1000  avgt   10  279.014 ± 1.189  us/op
RecordSerializationBench.deserializeRecords        10  avgt   10    8.537 ± 0.032  us/op
RecordSerializationBench.deserializeRecords       100  avgt   10   31.451 ± 0.083  us/op
RecordSerializationBench.deserializeRecords      1000  avgt   10  250.854 ± 2.772  us/op


With that, more objects means advantage over classical classes instead 
of disadvantage.


[1] 
http://cr.openjdk.java.net/~plevart/jdk-dev/RecordsDeserialization/RecordSerializationBench.java

[2] 
http://cr.openjdk.java.net/~plevart/jdk-dev/RecordsDeserialization/webrev.06/


Regards, Peter