Re: Proposal for back-porting JFR to OpenJDK8u

guangyu.zhu guangyu.zhu at
Tue Jan 29 11:41:35 UTC 2019

Hi there,

JFR backport patch has been uploaded to cr.openjdk. Please have a review for the patch.


The original patch comes from webrev: . We ported it to jdk8u192-b26 and passed most of the jfr jtreg tests on Linux/x86-64 platform. Some features related to Module, AOT and log level are removed because jdk8 does not support them. 

We have added a new option ‘EnableJFR’ to enable or disable the JFR feature. It’s disabled by default. To enable it, you can start java with ‘-XX:+EnableJFR’.  For example:
java -XX:+EnableJFR -XX:StartFlightRecording=duration=1m,filename=rec.jfr MyApp

When running the jtreg test, please add the extra option '-vmoption:-XX:+EnableJFR'. Otherwise the test case will not execute correctly. Here is an example of running jfr jtreg test:
make test JTREG_TEST_EXTRA_OPTIONS=-vmoption:-XX:+EnableJFR TEST=jdk_jfr

There is one more thing worth noting, please use jmc version 7.0 or later to open the jfr record file. 

Your suggestions and comments are welcome.

Guangyu Zhu
Sender:李三红(三红) <sanhong.lsh at>
Sent At:2018 Dec. 17 (Mon.) 21:21
Recipient:Andrew Haley <aph at>; Mario Torre <neugens.limasoftware at>
Cc:jdk8u-dev <jdk8u-dev at>
Subject:Re: Proposal for back-porting JFR to OpenJDK8u

Thanks for comments, we are preparing our internal patches for webrev.
In the meantime, Martijn/ Andrew mentioned we can use AdoptOpenJDK to produce technical preview build.
Would like to know this... can Martijn point us some guide somewhere?

发件人: Andrew Haley [mailto:aph at] 
发送时间: 2018年12月13日 3:03
收件人: Mario Torre <neugens.limasoftware at>; 李三红(三红) <sanhong.lsh at>
抄送: Volker Simonis <volker.simonis at>; jdk8u-dev at
主题: Re: Proposal for back-porting JFR to OpenJDK8u

On 12/12/18 1:44 PM, Mario Torre wrote:
> I think the first thing to do would be to post the patch for review, a 
> shared repository would make the review process a bit more complex I 
> think, and only makes sense if there is a need to work further on the 
> patch collectively.

Yes, exactly. That's the normal process, and it's the best place to start.

Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <>
EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671

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