Hi Peter,
patch and results look great!
My only real comment on this is that I think the microbenchmark would be
a valuable contribution, too.
It'd also be interesting to explore how poor performance would become if
we'd hit the (artificial) 11 layouts limit, e.g, by cycling through
10, 11, or 12 different shapes.
/Claes
On 2020-06-21 19:16, Peter Levart wrote:
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
