JFR chunks 2.0/2.1 specs?

[Jie Kang]

On Tue, Aug 31, 2021 at 4:30 AM Erik Gahlin <erik.gahlin at oracle.com> wrote:
>
> Hi,
>
> There is no spec. for the JFR file format. The change between 2.0 and 2.1 only applies to streaming. Once a recording is complete the format is exactly the same. What was added was the use of a few bits extension bits in the chunk header. You can do a diff of ChunkHeader to see the difference.
>
> The flush marker in the check point event, not used prior to JDK 14, but added in JDK 11 to future proof the format, now contains type information about a check point. This can be used to optimize parsing when streaming. You can see the CheckpointType class.

Okay, no worries. Thank you for the additional insight, it's appreciated.


Regards,

>
> Erik
> ________________________________
> From: hotspot-jfr-dev <hotspot-jfr-dev-retn at openjdk.java.net> on behalf of Jie Kang <jkang at redhat.com>
> Sent: Monday, August 30, 2021 9:20 PM
> To: hotspot-jfr-dev at openjdk.java.net <hotspot-jfr-dev at openjdk.java.net>
> Subject: JFR chunks 2.0/2.1 specs?
>
> Hi all,
>
> Does the jfr chunk have a spec (especially to compare 2.0 vs 2.1) that
> can be shared?  It would make things a little quicker for me over
> examining the chunk writing implementations in 11 and 17.
>
>
> Thanks,
> --
> Jie Kang
> Red Hat Canada
> https://keybase.io/jkang
> 1F5B34F61EF92DB4DCDDF195F034C81F60D402AA
>


-- 
Jie Kang
Associate Manager : Java Monitoring Team
Toronto Internship Program Lead
Red Hat Canada
https://keybase.io/jkang
1F5B34F61EF92DB4DCDDF195F034C81F60D402AA