RFR: 8319630: Monitor final audit log lacks separator

[Daniel D. Daugherty]

On Tue, 7 Nov 2023 14:01:08 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> There's a couple of problems with the "final audit" output for `is_busy` monitors.
> 
> 1) The contentions field lacks a ", " when `contentions()` returns 0
> 2) The owner field lacks a ", " when owner is non-null
> 
> Example output before the patch:
> 
> [20.122s][info][monitorinflation] 0x0000600003fb4010 100 0x0000080000200908 java.lang.ref.NativeReferenceQueue$Lock (is_busy: waiters=1, contentions=0owner=0x0000000000000000, cxq=0x0000000000000000, EntryList=0x0000000000000000)
> ``` 
> 
> Tested with manual inspection. I couldn't find a pre-existing test for this output, so my guess is that it's mainly for HotSpot developers?

Sorry for delay in reviewing this one.

> I also wonder why we fix the value of contentions and owner? It seems like the code wants to write 0s for the
> special-cases where is_busy will return false. It's unclear to me if it is worth doing this instead of just printing
> the raw values.

The idea was to hide any transient async monitor deflation values from any log output consumers.

Nice catch on the missing punction.

Thumbs up.

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PR Comment: https://git.openjdk.org/jdk/pull/16541#issuecomment-1815259893