Support to customize the collect period of JVM relative metrics.

[IceSoda177]

Support to customize the collect period of JVM relative metrics.

• [] If this is non-trivial feature, paste the links/URLs to the design doc.

• Update the documentation to include this new feature.

• Tests(including UT, IT, E2E) are added to verify the new feature.

• If it's UI related, attach the screenshots below.

• If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes Support to customize the report period of JVM relative metrics. skywalking#10179.

• Update the CHANGES log.

[nisiyong]

It seems the OAP side will calculate GC time per second. This change should consider more.

[wu-sheng]

You should not change the default value.

[wu-sheng]

It is rarely to see thousands threads for a health service.

[wu-sheng]

It seems the OAP side will calculate GC time per second. This change should consider more.

Could you list which metrics?

[IceSoda177]

It seems the OAP side will calculate GC time per second. This change should consider more.

I don't see any necessary gc metrics calculation for every second.
The OAP use sum() method in OAL to aggregate gc metrcis, including time and count of different gc phase.
After that, it will generat the final gc metrics of 1min.

On the other hand, Agent record lastest time or count of diff gc phase, and use them to create new metrics in next time collection.
So, I think it's fine if anyone want to change their JVM metrics collect period

[IceSoda177]

You should not change the default value.

My bad

[IceSoda177]

You should not change the default value.

The default value stays and the configuration.md is updated.
Excuse me for my first pr. ＾-＾

[wu-sheng]

Let's wait for @nisiyong feedback. And the CI would fail,

#427 (comment)

I need to wait for both things.

[nisiyong]

I may have just got COVID-19, I will check it when I get better😿

[wu-sheng]

I may have just got COVID-19, I will check it when I get better😿

Take care. I am suffering symptoms too. 4 days fever, but it is going down.

[IceSoda177]

Tack care guys.
I'm lucky so far, but we really out of meds here.

[wu-sheng]

@lujiajing1126 I made this. As #429 missed to correct versions.

[lujiajing1126]

Thx, I forgot to fix it there

[nisiyong]

It seems the OAP side will calculate GC time per second. This change should consider more.

@dylanforest @wu-sheng Sorry for my late reply, this PR looks good to me.

And I should correct what I said before, the agent side will calculate the GC time rather than the OAP side.

skywalking-java/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/jvm/gc/GCModule.java

Line 56 in cd84ba2

gcTime = time - lastYGCCollectionTime;

Currently, the metrics are stored at a minute level in the backend, so I think this is fine.

[wu-sheng]

It seems the OAP side will calculate GC time per second. This change should consider more.

@dylanforest @wu-sheng Sorry for my late reply, this PR looks good to me.

And I should correct what I said before, the agent side will calculate the GC time rather than the OAP side.

skywalking-java/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/jvm/gc/GCModule.java

Line 56 in cd84ba2

gcTime = time - lastYGCCollectionTime;

Currently, the metrics are stored at a minute level in the backend, so I think this is fine.

Thanks for the clarification.

Currently, the metrics are stored at a minute level in the backend

About this, I want to add a little more. The metrics are SUMed in minute/hour/day. From the visualization part, it shows VM GC Time (ms) and JVM GC Count in the time buckets of the range.

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I agree, this change should be fine.

[wu-sheng]

BTW @nisiyong Are you feeling better now?

[wu-sheng]

LGTM.

@dylanforest I added Unit is second. to the doc and config, to make the new config more clear.

[nisiyong]

BTW @nisiyong Are you feeling better now?

Thanks for your concern, I am much better now. Had a fever for 3 days and it was really painful.

[wu-sheng]

BTW @nisiyong Are you feeling better now?

Thanks for your concern, I am much better now. Had a fever for 3 days and it was really painful.

Same here. 3 days fever. Take enough rest. This doesn't go away immediately. The fever could be back.