RFR: 8324646: Avoid Class.forName in SecureRandom constructor [v3]

[Weijun Wang]

On Thu, 1 Feb 2024 10:39:27 GMT, Oli Gillespie <ogillespie at openjdk.org> wrote:

>> Avoid expensive `Class.forName` call when constructing Providers such as `SecureRandom` which take constructor parameters. This can easily be cached in EngineDescription (this cache already existed before, it was removed in [JDK-8280970](https://bugs.openjdk.org/browse/JDK-8280970) as unused, I'm bringing it back unchanged to support this new usage).
>> 
>> Benchmark results on my Linux x86 host show around a 20% reduction in time to create a new `SecureRandom` instance. Most of the remaining overhead is due to a failing constructor lookup - see [JDK-8324648](https://bugs.openjdk.org/browse/JDK-8324648).
>> 
>> 
>> Before
>> newSecureRandom  avgt  2930 ± 50  ns/op
>> 
>> After
>> newSecureRandom  avgt  2400 ± 33  ns/op
>> 
>> 
>> I have seen multiple real-world applications which call `new SecureRandom()` on the hot path, so I believe efficiency here is important.
>
> Oli Gillespie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use class literals instead of forName

LGTM.

BTW, is there any change in benchmark scores?

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Marked as reviewed by weijun (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17559#pullrequestreview-1865113779