Shenandoah Events

[Ken Dobson]

Hi,

They are being emitted correctly, we realized to get them to show in JMC
you must enable experimental events in the Preferences. There is one issue
with the events is the values of type *RegionState* display N/A because
they require serialization I believe. I am currently looking into adding a
serializer to the patch.

Ken

On Mon, Jan 14, 2019 at 3:27 PM <zgu at redhat.com> wrote:

> On Fri, 2019-01-11 at 15:20 -0500, Ken Dobson wrote:
> > Hi,
> >
> > Actually it shouldn't be in the default jfc file, you are able to
> > configure the events yourself by enabling them before you begin a
> > recording. You wouldn't want these events enabled by default, they
> > should be enabled explicitly by those who would like to use them.
> >
> > That being said I have been unable to get the events to show up in
> > the event browser. Using the jfr command from the CLI it appears the
> > events are being emitted correctly so it seems it's an issue on the
> > JMC side that I am currently attempting to solve.
> >
> Yes, you can enable the events at the point of recording from JMC, and
> seems that events are emitted.
>
> jfr summary ...
>
>  Event Type                              Count  Size (bytes)
> =============================================================
>  jdk.ShenandoahHeapRegionStateChange   3843823      94125936
>  jdk.ShenandoahHeapRegionInformation     63072       1332094
>
> I need to look into state change events, seems excessive ...
>
> Thanks,
>
> -Zhengyu
>
>
> > Ken
> >
> > On Fri, Jan 11, 2019 at 1:16 PM Jie Kang <jkang at redhat.com> wrote:
> > > On Fri, Jan 11, 2019 at 1:02 PM Jie Kang <jkang at redhat.com> wrote:
> > > >
> > > > On Fri, Jan 11, 2019 at 8:40 AM <zgu at redhat.com> wrote:
> > > > >
> > > > > Hi Guys,
> > > > >
> > > > > Here is my initial implementation of Shenandoah heap layout JFR
> > > events:
> > > > >
> > > > > http://cr.openjdk.java.net/~zgu/shenandoah/jfr_sh_heap_layout/w
> > > ebrev.00
> > > > > /
> > > > >
> > > > > The patch is good for jdk/jdk and shenandoah/jdk repos. I have
> > > no idea
> > > > > how to test it without JMC counterpart. If you have any
> > > suggestions,
> > > > > please let me know.
> > >
> > > Hi,
> > >
> > > Also, the default jfc file (java flight recording configuration)
> > > does
> > > not have the Shenandoah events enabled so they won't be fired
> > > unless
> > > you supply a custom jfc, or maybe patch the repo to produce a
> > > default.jfc that does have them enabled. It looks like ZGC related
> > > events are there so it should be fine to add Shenandoah ones as
> > > well.
> > >
> > > The jfc files in jdk/jdk are default.jfc and profile.jfc @
> > > http://hg.openjdk.java.net/jdk/jdk/file/fbc921683f02/src/jdk.jfr/sh
> > > are/conf/jfr
> > >
> > > Assuming the events work, they will be seen then.
> > >
> > >
> > > Regards,
> > >
> > > >
> > > > Hi,
> > > >
> > > > For testing without JMC, you can add options to the JVM to create
> > > a
> > > > flight recording and then use the CLI tool 'jfr' that is part of
> > > > OpenJDK to examine the jfr file for the existence of Shenandoah
> > > > events.
> > > >
> > > > Some hopefully helpful terminal output from a build of jdk/jdk:
> > > >
> > > > [jkang at unused-10-15-17-52 linux-x86_64-server-release]$
> > > jdk/bin/jfr
> > > > Tool for working with Flight Recorder files (.jfr)
> > > >
> > > > Before using this tool, you must have a recording file.
> > > > A file can be created by starting a recording from command line:
> > > >
> > > >  java
> > > -XX:StartFlightRecording:filename=recording.jfr,duration=30s ...
> > > >
> > > > A recording can also be started on already running Java Virtual
> > > Machine:
> > > >
> > > >  jcmd (to list available pids)
> > > >  jcmd <pid> JFR.start
> > > >
> > > > Recording data can be dumped to file using the JFR.dump command:
> > > >
> > > >  jcmd <pid> JFR.dump filename=recording.jfr
> > > >
> > > > The contents of the recording can then be printed, for example:
> > > >
> > > >  jfr print recording.jfr
> > > >
> > > >  jfr print --events CPULoad,GarbageCollection recording.jfr
> > > >
> > > >  jfr print --json --events CPULoad recording.jfr
> > > >
> > > >  jfr print --categories "GC,JVM,Java*" recording.jfr
> > > >
> > > >  jfr print --events "jdk.*" --stack-depth 64 recording.jfr
> > > >
> > > >  jfr summary recording.jfr
> > > >
> > > >  jfr metadata recording.jfr
> > > >
> > > > For more information about available commands, use 'jfr help'
> > > >
> > > >
> > > > Regards,
> > > >
> > > > >
> > > > > Hopefully, it is enough for you to get things started.
> > > > >
> > > > > Thanks,
> > > > >
> > > > > -Zhengyu
> > > > >
> > > > > > On Wed, 2019-01-09 at 18:14 +0100, Mario Torre wrote:
> > > > > > > Hello all!
> > > > > > >
> > > > > > > I would like to have a quick meeting to discuss the JFR
> > > events in
> > > > > > > shenandoah, when would be a good time?
> > > > > > >
> > > > > > > I have a slot tomorrow at 3 PM (9AM your time I believe),
> > > would
> > > > > > > that
> > > > > > > work for you?
> > > > > > >
> > > > > > > Cheers,
> > > > > > > Mario
> > > > > > >
>