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Support ZGC in JvmGcMetrics #2305

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shakuzen opened this issue Oct 26, 2020 · 4 comments · Fixed by #2306
Closed

Support ZGC in JvmGcMetrics #2305

shakuzen opened this issue Oct 26, 2020 · 4 comments · Fixed by #2306
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enhancement A general enhancement
Milestone
1.6.0

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@shakuzen
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shakuzen commented Oct 26, 2020 •
edited

Similar to #1861 for ZGC. See the OpenJDK Wiki for ZGC for more information on it. In addition to GC pause time metric (jvm.gc.pause) which should already work, we should support the following when using ZGC:

  • jvm.gc.max.data.size
  • jvm.gc.live.data.size
  • jvm.gc.memory.allocated
@shakuzen shakuzen added the enhancement A general enhancement label Oct 26, 2020
@shakuzen shakuzen added this to the 1.6.0 milestone Oct 26, 2020
shakuzen added a commit to shakuzen/micrometer that referenced this issue Oct 26, 2020
@shakuzen
Support non-generational garbage collector metrics
bcda8d5 
There were some assumptions in JvmGcMetrics that the garbage collector was generational, with a designated young and old region. ZGC and Shenandoah are examples of OpenJDK garbage collectors that are not generational. GC metrics should be properly recorded with these changes.

Resolves micrometer-metrics#1861
Resolves micrometer-metrics#2305
@shakuzen shakuzen mentioned this issue Oct 26, 2020
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shakuzen added a commit that referenced this issue Oct 28, 2020
@shakuzen
Support non-generational garbage collector metrics (#2306)
6d3fec0 
There were assumptions in JvmGcMetrics that the garbage collector was generational, with designated young and old regions. ZGC and Shenandoah are examples of OpenJDK garbage collectors that are not generational. GC metrics should be properly recorded for them with these changes.

Resolves #1861
Resolves #2305
This was referenced Jun 26, 2021
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@crohit
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crohit commented Jan 20, 2024

Hi @shakuzen - sorry to bug on this old post with this question, but I recently upgraded to zgc for a repo at work and am wondering what are the metrics available for zgc.

action:end_of_gc_pause,cause:proactive
action:end_of_gc_pause,cause:warmup

These are the only ones I see. Are there more metrics I should be seeing? Including any other causes and actions?

@shakuzen
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Are there more metrics I should be seeing? Including any other causes and actions?

Not until more actions and causes happen in your application after JvmGcMetrics is bound to a registry. The metrics are dynamically registered in response to GC notifications. Until GC events happen in your application, there won't be any metrics recorded for them. We do not register metrics for GC events until they happen. You could, for example, force a GC in your application (with e.g. System.gc() or JMX or jconsole) and see GC metrics recorded in response to that. Does that make sense and clear up what's happening?

@crohit
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crohit commented Jan 24, 2024

Are there more metrics I should be seeing? Including any other causes and actions?

Not until more actions and causes happen in your application after JvmGcMetrics is bound to a registry. The metrics are dynamically registered in response to GC notifications. Until GC events happen in your application, there won't be any metrics recorded for them. We do not register metrics for GC events until they happen. You could, for example, force a GC in your application (with e.g. System.gc() or JMX or jconsole) and see GC metrics recorded in response to that. Does that make sense and clear up what's happening?

Ah yeah that clears up- Let me go back and look into this. Are there other notifications which are emitted on GC that I know I should look out for when a GC is run?

@shakuzen
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Are there other notifications which are emitted on GC that I know I should look out for when a GC is run?

We don't keep an exhaustive list because it is up to what the garbage collector has implemented, which can change between versions of the JVM. Unfortunately, I'm not aware of good documentation on this from each collector either.

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Support non-generational garbage collector metrics shakuzen/micrometer
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