RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

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RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
This is quite trivial.

jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).

Example output:

Settings:
MaxMetaspaceSize: 17179869184,00 GB
CompressedClassSpaceSize: 1,00 GB
Initial GC threshold: 20,75 MB
Current GC threshold: 21,50 MB
CDS: on
MetaspaceReclaimPolicy: balanced
-------
Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.

-------------

Commit messages:
 - Start

Changes: https://git.openjdk.java.net/jdk/pull/2686/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2686&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262163
  Stats: 10 lines in 1 file changed: 10 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2686.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2686/head:pull/2686

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Yang Yi
On Tue, 23 Feb 2021 06:08:08 GMT, Thomas Stuefe <[hidden email]> wrote:

> This is quite trivial.
>
> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>
> Example output:
>
> Settings:
> MaxMetaspaceSize: 17179869184,00 GB
> CompressedClassSpaceSize: 1,00 GB
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> CDS: on
> MetaspaceReclaimPolicy: balanced
> -------
> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.

Looks good! IMHO, can we simply reorder these settings? i.e.

Settings:
AppCDS: on
Initial GC threshold: 20,75 MB
Current GC threshold: 21,50 MB
MaxMetaspaceSize: 17179869184,00 GB
MetaspaceReclaimPolicy: balanced
CompressedClassSpaceSize: 1,00 GB

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
On Tue, 23 Feb 2021 06:28:13 GMT, Yang Yi <[hidden email]> wrote:

>> This is quite trivial.
>>
>> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>>
>> Example output:
>>
>> Settings:
>> MaxMetaspaceSize: 17179869184,00 GB
>> CompressedClassSpaceSize: 1,00 GB
>> Initial GC threshold: 20,75 MB
>> Current GC threshold: 21,50 MB
>> CDS: on
>> MetaspaceReclaimPolicy: balanced
>> -------
>> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.
>
> Looks good! IMHO, can we simply reorder these settings? i.e.
>
> Settings:
> AppCDS: on
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> MaxMetaspaceSize: 17179869184,00 GB
> MetaspaceReclaimPolicy: balanced
> CompressedClassSpaceSize: 1,00 GB

Hi Yang,

> Looks good! IMHO, can we simply reorder these settings? i.e.
>
> Settings:
> AppCDS: on
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> MaxMetaspaceSize: 17179869184,00 GB
> MetaspaceReclaimPolicy: balanced
> CompressedClassSpaceSize: 1,00 GB

Sure, I can reorder that, but on what base? Alphabetically?

..Thomas

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Yang Yi
On Tue, 23 Feb 2021 07:58:58 GMT, Thomas Stuefe <[hidden email]> wrote:

>> Looks good! IMHO, can we simply reorder these settings? i.e.
>>
>> Settings:
>> AppCDS: on
>> Initial GC threshold: 20,75 MB
>> Current GC threshold: 21,50 MB
>> MaxMetaspaceSize: 17179869184,00 GB
>> MetaspaceReclaimPolicy: balanced
>> CompressedClassSpaceSize: 1,00 GB
>
> Hi Yang,
>
>> Looks good! IMHO, can we simply reorder these settings? i.e.
>>
>> Settings:
>> AppCDS: on
>> Initial GC threshold: 20,75 MB
>> Current GC threshold: 21,50 MB
>> MaxMetaspaceSize: 17179869184,00 GB
>> MetaspaceReclaimPolicy: balanced
>> CompressedClassSpaceSize: 1,00 GB
>
> Sure, I can reorder that, but on what base? Alphabetically?
>
> ..Thomas

Maybe good-looking based ordering : )

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
On Wed, 24 Feb 2021 02:59:06 GMT, Yi Yang <[hidden email]> wrote:

> Maybe good-looking based ordering : )

In that case I rather keep it as it is, since its ordered by subjective importance :)

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Lutz Schmidt
In reply to this post by Thomas Stuefe
On Tue, 23 Feb 2021 06:08:08 GMT, Thomas Stuefe <[hidden email]> wrote:

> This is quite trivial.
>
> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>
> Example output:
>
> Settings:
> MaxMetaspaceSize: 17179869184,00 GB
> CompressedClassSpaceSize: 1,00 GB
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> CDS: on
> MetaspaceReclaimPolicy: balanced
> -------
> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.

The changes look good to me.

What I don't like is the printout of the MaxMetaspaceSize value. It is outrageously big. The value displayed corresponds to 0x400000000 GB. Looking at the code, I would expect "unlimited" to be printed. Can you explain why it is not?

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Lutz Schmidt
On Wed, 24 Feb 2021 17:11:20 GMT, Lutz Schmidt <[hidden email]> wrote:

>> This is quite trivial.
>>
>> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>>
>> Example output:
>>
>> Settings:
>> MaxMetaspaceSize: 17179869184,00 GB
>> CompressedClassSpaceSize: 1,00 GB
>> Initial GC threshold: 20,75 MB
>> Current GC threshold: 21,50 MB
>> CDS: on
>> MetaspaceReclaimPolicy: balanced
>> -------
>> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.
>
> The changes look good to me.
>
> What I don't like is the printout of the MaxMetaspaceSize value. It is outrageously big. The value displayed corresponds to 0x400000000 GB. Looking at the code, I would expect "unlimited" to be printed. Can you explain why it is not?

I just found JDK-8262099. It deals with the effect I disliked in my review comment. So, once JDK-8262099 is in, I am happy with this change here.

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
On Wed, 24 Feb 2021 17:20:00 GMT, Lutz Schmidt <[hidden email]> wrote:

> I just found JDK-8262099. It deals with the effect I disliked in my review comment. So, once JDK-8262099 is in, I am happy with this change here.

Thanks Lutz!  Yes, I left the fix for MaxMetaspaceSize out to not interfere with Yi Yang's change.

Cheers, Thomas

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
In reply to this post by Lutz Schmidt
On Wed, 24 Feb 2021 17:20:00 GMT, Lutz Schmidt <[hidden email]> wrote:

>> The changes look good to me.
>>
>> What I don't like is the printout of the MaxMetaspaceSize value. It is outrageously big. The value displayed corresponds to 0x400000000 GB. Looking at the code, I would expect "unlimited" to be printed. Can you explain why it is not?
>
> I just found JDK-8262099. It deals with the effect I disliked in my review comment. So, once JDK-8262099 is in, I am happy with this change here.

@RealLucy Can you please approve then? Thanks!

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Withdrawn: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
In reply to this post by Thomas Stuefe
On Tue, 23 Feb 2021 06:08:08 GMT, Thomas Stuefe <[hidden email]> wrote:

> This is quite trivial.
>
> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>
> Example output:
>
> Settings:
> MaxMetaspaceSize: 17179869184,00 GB
> CompressedClassSpaceSize: 1,00 GB
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> CDS: on
> MetaspaceReclaimPolicy: balanced
> -------
> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.

This pull request has been closed without being integrated.

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Lutz Schmidt
In reply to this post by Thomas Stuefe
On Tue, 23 Feb 2021 06:08:08 GMT, Thomas Stuefe <[hidden email]> wrote:

> This is quite trivial.
>
> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>
> Example output:
>
> Settings:
> MaxMetaspaceSize: 17179869184,00 GB
> CompressedClassSpaceSize: 1,00 GB
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> CDS: on
> MetaspaceReclaimPolicy: balanced
> -------
> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.

With the other change: LGTM.

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
On Wed, 24 Feb 2021 20:27:55 GMT, Lutz Schmidt <[hidden email]> wrote:

>> This is quite trivial.
>>
>> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>>
>> Example output:
>>
>> Settings:
>> MaxMetaspaceSize: 17179869184,00 GB
>> CompressedClassSpaceSize: 1,00 GB
>> Initial GC threshold: 20,75 MB
>> Current GC threshold: 21,50 MB
>> CDS: on
>> MetaspaceReclaimPolicy: balanced
>> -------
>> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.
>
> With the other change: LGTM.

@RealLucy Can you please approve? As in, press the "Approve" button? :) Thanks!

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686
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Re: RFR: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Lutz Schmidt
In reply to this post by Thomas Stuefe
On Tue, 23 Feb 2021 06:08:08 GMT, Thomas Stuefe <[hidden email]> wrote:

> This is quite trivial.
>
> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>
> Example output:
>
> Settings:
> MaxMetaspaceSize: 17179869184,00 GB
> CompressedClassSpaceSize: 1,00 GB
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> CDS: on
> MetaspaceReclaimPolicy: balanced
> -------
> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.

LGTM.

-------------

Marked as reviewed by lucy (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/2686
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Integrated: JDK-8262163: Extend settings printout in jcmd VM.metaspace

Thomas Stuefe
In reply to this post by Thomas Stuefe
On Tue, 23 Feb 2021 06:08:08 GMT, Thomas Stuefe <[hidden email]> wrote:

> This is quite trivial.
>
> jcmd VM.metaspace prints metaspace settings at the end of its printout. Missing from that printout are some settings which would be nice to see here, eg the GC thresholds and CDS settings (nice to know since CDS affects how metaspace is used).
>
> Example output:
>
> Settings:
> MaxMetaspaceSize: 17179869184,00 GB
> CompressedClassSpaceSize: 1,00 GB
> Initial GC threshold: 20,75 MB
> Current GC threshold: 21,50 MB
> CDS: on
> MetaspaceReclaimPolicy: balanced
> -------
> Tests: Manually ran runtime/Metaspace/PrintMetaspaceDcmd.java.

This pull request has now been integrated.

Changeset: ea48a0bb
Author:    Thomas Stuefe <[hidden email]>
URL:       https://git.openjdk.java.net/jdk/commit/ea48a0bb
Stats:     10 lines in 1 file changed: 10 ins; 0 del; 0 mod

8262163: Extend settings printout in jcmd VM.metaspace

Reviewed-by: lucy

-------------

PR: https://git.openjdk.java.net/jdk/pull/2686