RFR: 8319630: Monitor final audit log lacks separator

[Stefan Karlsson]

On Thu, 16 Nov 2023 20:24:58 GMT, Daniel D. Daugherty <dcubed 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.

Thanks @dcubed-ojdk for reviewing this.

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PR Comment: https://git.openjdk.org/jdk/pull/16541#issuecomment-1815268259