RFR: 8259808: Add JFR event to detect GC locker stall [v5]

[Denghui Dong]

On Tue, 26 Jan 2021 16:49:37 GMT, Erik Gahlin <egahlin at openjdk.org> wrote:

>> Denghui Dong has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add descriptions and fix the format problem
>
> src/hotspot/share/jfr/metadata/metadata.xml line 1094:
> 
>> 1092: 
>> 1093:   <Event name="GCLocker" category="Java Virtual Machine, GC, Detailed" description="GC Locker Information" label="GC Locker" startTime="true" thread="true" stackTrace="true">
>> 1094:     <Field type="uint" name="lockCount" label="Lock Count" description="the number of java threads in a critical section when the GC locker is started" />
> 
> I would suggest changing this to:
>  
> "The number of Java threads in a critical section when the GC locker is started"
> "The number of Java threads stalled by the GC locker"

changed.

> src/hotspot/share/jfr/metadata/metadata.xml line 1093:
> 
>> 1091:   </Event>
>> 1092: 
>> 1093:   <Event name="GCLocker" category="Java Virtual Machine, GC, Detailed" description="GC Locker Information" label="GC Locker" startTime="true" thread="true" stackTrace="true">
> 
> "GC Locker Information" is not very useful. Remove the description completely or provide more information.

removed.

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PR: https://git.openjdk.java.net/jdk/pull/2088