[threeten-dev] Ser performance

[Stephen Colebourne]

See also
http://blog.joda.org/2010/02/serialization-shared-delegates_9131.html

The format focusses on reducing the size of a single object, by
reducing the header (short class name Ser), sharing the header (shared
between all classes in the same package) and an optimal data format
(although it could be reduced more, 2 byte saving in LocalDate would
be easy).

Your test averages the message size over 1000 stores, which naturally
ignores the cost of the header. But its the header cost which
dominates in typical application messages.

Your test also doesn't place multiple classes from the same package in
the same stream, say 2 LocalDates, 2 LocalTimes a Period and a
Duration. The Ser approach should shine there.

Your "simple" version is still quite advanced, using the Unsafe class.
The simplest serialization would simply be to have no readObject
writeObject other than for validation.

I don't understand why LocalTime size would be larger and speed slower
than the alternative.

Stephen



On 5 March 2013 23:41, Xueming Shen <xueming.shen at oracle.com> wrote:
> Just tried a non-scientific performance measurement on the proxy pattern
> used by the Ser spec/impl, here is the data from the simple benchmark
> SerTest.java.
>
> It appears the
> (1) expected slowdown is obvious on the serialization side, particular in
> LocalTime
> (2) the de-serialization side may be just fine.
>
> http://cr.openjdk.java.net/~sherman/jdk8_threeten/serPerm/
> http://cr.openjdk.java.net/~sherman/jdk8_threeten/serPerm/SerTest.java
>
> ---------------------Proxy pattern----------------
> java SerTest 1000
> --------LocalDate--------
> serSize=16
> Writing: 6655
> Reading: 3224
> --------LocalTime--------
> serSize=17
> Writing: 6125
> Reading: 2937
> --------LocalDateTime--------
> serSize=23
> Writing: 6188
> Reading: 3383
>
> ---------------------Simple/direct serialization-------
> --------LocalDate--------
> serSize=14
> Writing: 3418
> Reading: 3836
> --------LocalTime--------
> serSize=13
> Writing: 2756
> Reading: 2358
> --------LocalDateTime--------
> serSize=22
> Writing: 3266
> Reading: 4407
>