RFR: 8281631: HashMap copy constructor and putAll can over-allocate table [v22]

[XenoAmess]

On Sun, 20 Feb 2022 20:03:07 GMT, XenoAmess <duke at openjdk.java.net> wrote:

> > You should run benchmarks to see how bad the lookup performance degrades after you saves memory used by the hash table.
> 
> OK, would find some time for it.

@liach which jmh test should I run by the way?

Or is there some commandline tools for this?

I found nothing related to IdentityHashMap under `test/micro`

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PR: https://git.openjdk.java.net/jdk/pull/7431