RFR: 8317562: [JFR] Compilation queue statistics [v3]

[Erik Gahlin]

On Sat, 28 Oct 2023 01:52:08 GMT, Mat Carter <macarte at openjdk.org> wrote:

>> Adding a new periodic jfr event to monitor and output statistics for the compiler queues.  You will see one event per compiler queue (c1 and c2)
>> 
>> Passes tier1 on linux (x86) and mac (aarch64)
>
> Mat Carter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Addressed review comments

src/hotspot/share/jfr/metadata/metadata.xml line 853:

> 851:   <Event name="CompilerQueueUtilization" category="Java Virtual Machine, Compiler" label="Compiler Queue Utilization" period="everyChunk">
> 852:     <Field type="CompilerType" name="compiler" label="Compiler" />
> 853:     <Field type="long" contentType="hertz" name="ingress" label="Ingress" description="Number of added requests per second"/>

Could we use other terms then ingress and egress? Something that is more in general use,

src/hotspot/share/jfr/metadata/metadata.xml line 855:

> 853:     <Field type="long" contentType="hertz" name="ingress" label="Ingress" description="Number of added requests per second"/>
> 854:     <Field type="long" contentType="hertz" name="egress" label="Egress" description="Number of removed requests per second"/>
> 855:     <Field type="long" name="size" label="Size"/>

The label could be more clarifying? Queue Size?

src/hotspot/share/jfr/metadata/metadata.xml line 856:

> 854:     <Field type="long" contentType="hertz" name="egress" label="Egress" description="Number of removed requests per second"/>
> 855:     <Field type="long" name="size" label="Size"/>
> 856:     <Field type="long" name="peak" label="Peak Size"/>

peakQueueSize?

src/hotspot/share/jfr/metadata/metadata.xml line 861:

> 859:     <Field type="long" name="totalAdded" label="Total Added"/>
> 860:     <Field type="long" name="totalRemoved" label="Total Removed"/>
> 861:     <Field type="int" name="compilerThreadCount" label="Number of Compiler Threads for this queue"/>

The label should be short and use headline-style capitalization, how about "Compiler Thread Count"?
https://docs.oracle.com/en/java/javase/21/docs/api/jdk.jfr/jdk/jfr/Label.html

src/hotspot/share/jfr/periodic/jfrCompilerQueueUtilization.cpp line 53:

> 51:     return 0;
> 52:   }
> 53:   return ((current - old) * NANOSECS_PER_SEC) / interval.nanoseconds();

Shouldn't it be ticks per second here?

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PR Review Comment: https://git.openjdk.org/jdk/pull/16211#discussion_r1375505798
PR Review Comment: https://git.openjdk.org/jdk/pull/16211#discussion_r1375508747
PR Review Comment: https://git.openjdk.org/jdk/pull/16211#discussion_r1375508798
PR Review Comment: https://git.openjdk.org/jdk/pull/16211#discussion_r1375505254
PR Review Comment: https://git.openjdk.org/jdk/pull/16211#discussion_r1375508417