5 ms·

I'm the author, ask me things.

by parttimenerd 3y ago

znpy 3y ago
What's your recommendation about learning how to properly use JFR and Java mission control?
- parttimenerd 3y ago
  I collected some information here: https://mostlynerdless.de/profiling-talks/ https://mostlynerdless.de/profiling-talks/
  - znpy 3y ago
    Thanks!
TedDoesntTalk 3y ago
Can you give some real world examples when to use JFR custom events? The Minecraft example is not helpful when I know nothing about Minecraft.
- gunnarmorling 3y ago
  I've written about two applications of custom JFR events in the past: * Monitoring invocations of a REST API: https://www.morling.dev/blog/rest-api-monitoring-with-custom-jdk-flight-recorder-events/ https://www.morling.dev/blog/rest-api-monitoring-with-custom... * Tracking SQL queries issued by your ORM: https://www.javaadvent.com/2021/12/keep-your-sql-in-check-with-flight-recorder-jmc-agent-and-jfrunit.html https://www.javaadvent.com/2021/12/keep-your-sql-in-check-wi... The latter is about injecting event-emitting code with a Java Agent rather than manually implementing custom events (latest Hibernate ORM version comes with JFR support OOTB, too).
  - gred 3y ago
    > Monitoring invocations of a REST API Yep, we use custom JFR events to track API calls and correlate them to other built-in JFR events and statistics (garbage collection, memory use, allocations, CPU use, deadlocks, etc).
    - parttimenerd 3y ago
      You might be interested in a proposal by Jaroslav Bachorik to add context into JFR. I wrote a short introduction on my blog "Putting JFR into Context" (https://mostlynerdless.de/blog/2023/10/19/putting-jfr-into-context/ https://mostlynerdless.de/blog/2023/10/19/putting-jfr-into-c...)
  - parttimenerd 3y ago
    Thank you Gunnar, I linked to your blog post (and even linked to it already in my previous blog post "Custom JFR Events: A Short Introduction" https://mostlynerdless.de/blog/2023/11/20/custom-jfr-events-a-short-introduction/ https://mostlynerdless.de/blog/2023/11/20/custom-jfr-events-...)
lsaferite 3y ago
Just some feedback. Maybe explain what JFR is for the random visitors that have no clue. If you did then I apologize for missing it.
- elliotec 3y ago
  Agreed. In the first picture, you can see it stands for "Java FlightRecorder," but there's no explanation of what that is or does. A profiler?
  - FrustratedMonky 3y ago
    Second this. Even when someone said it was in screen shot, it took a minute to go back and refocus to find it. But. No knock on this guy. I find all STEM writing could be helped a little with some up front what/why/how in introduction. I want to dig this, but on first scan through, I have no idea what this is doing or why it is cool. So, for getting an article out, if I'm a casual that isn't a die hard user of JFR, then what makes me want to dig deeper? Of course, maybe the goal isn't a wider readership.
    - parttimenerd 3y ago
      I linked now to articles that provide you with more information.
  - lsaferite 3y ago
    I did go look up JFR when I had no idea what it was. I was just trying to give them a gentle suggestion that explaining the tool, even in 1 sentence, would be helpful.
- parttimenerd 3y ago
  Thanks for the feedback, I added a small disclaimer at the beginning of the article, telling the reader what JFR is and where to find more information.
  - 3y ago
xcdzvyn 3y ago
The Minecraft Wiki community is moving away from Fandom to the self-hosted https://minecraft.wiki/ https://minecraft.wiki/. Could you update your article to reflect that, by any chance? Edit: Wow! You've never played Minecraft before? That's crazy!
- parttimenerd 3y ago
  Thanks, I fixed it. > Edit: Wow! You've never played Minecraft before? That's crazy! I don't play computer games (the last game I played was "Thomas was alone"), but I know people that play it more often. Edit: Link to the game https://de.wikipedia.org/wiki/Thomas_Was_Alone https://de.wikipedia.org/wiki/Thomas_Was_Alone. Nowadays, I like to play whack-a-mole with bugs in the OpenJDK.
  - xcdzvyn 3y ago
    Thanks! And thank you for your work :)
    - parttimenerd 3y ago
      I'm happy for any reader of my blog :)

I'm the author, ask me things.

znpy 3y ago

What's your recommendation about learning how to properly use JFR and Java mission control?

parttimenerd 3y ago
I collected some information here: https://mostlynerdless.de/profiling-talks/ https://mostlynerdless.de/profiling-talks/
- znpy 3y ago
  Thanks!

TedDoesntTalk 3y ago

Can you give some real world examples when to use JFR custom events? The Minecraft example is not helpful when I know nothing about Minecraft.

gunnarmorling 3y ago
I've written about two applications of custom JFR events in the past: * Monitoring invocations of a REST API: https://www.morling.dev/blog/rest-api-monitoring-with-custom-jdk-flight-recorder-events/ https://www.morling.dev/blog/rest-api-monitoring-with-custom... * Tracking SQL queries issued by your ORM: https://www.javaadvent.com/2021/12/keep-your-sql-in-check-with-flight-recorder-jmc-agent-and-jfrunit.html https://www.javaadvent.com/2021/12/keep-your-sql-in-check-wi... The latter is about injecting event-emitting code with a Java Agent rather than manually implementing custom events (latest Hibernate ORM version comes with JFR support OOTB, too).
- gred 3y ago
  > Monitoring invocations of a REST API Yep, we use custom JFR events to track API calls and correlate them to other built-in JFR events and statistics (garbage collection, memory use, allocations, CPU use, deadlocks, etc).
  - parttimenerd 3y ago
    You might be interested in a proposal by Jaroslav Bachorik to add context into JFR. I wrote a short introduction on my blog "Putting JFR into Context" (https://mostlynerdless.de/blog/2023/10/19/putting-jfr-into-context/ https://mostlynerdless.de/blog/2023/10/19/putting-jfr-into-c...)
- parttimenerd 3y ago
  Thank you Gunnar, I linked to your blog post (and even linked to it already in my previous blog post "Custom JFR Events: A Short Introduction" https://mostlynerdless.de/blog/2023/11/20/custom-jfr-events-a-short-introduction/ https://mostlynerdless.de/blog/2023/11/20/custom-jfr-events-...)

lsaferite 3y ago

Just some feedback. Maybe explain what JFR is for the random visitors that have no clue. If you did then I apologize for missing it.

elliotec 3y ago
Agreed. In the first picture, you can see it stands for "Java FlightRecorder," but there's no explanation of what that is or does. A profiler?
- FrustratedMonky 3y ago
  Second this. Even when someone said it was in screen shot, it took a minute to go back and refocus to find it. But. No knock on this guy. I find all STEM writing could be helped a little with some up front what/why/how in introduction. I want to dig this, but on first scan through, I have no idea what this is doing or why it is cool. So, for getting an article out, if I'm a casual that isn't a die hard user of JFR, then what makes me want to dig deeper? Of course, maybe the goal isn't a wider readership.
  - parttimenerd 3y ago
    I linked now to articles that provide you with more information.
- lsaferite 3y ago
  I did go look up JFR when I had no idea what it was. I was just trying to give them a gentle suggestion that explaining the tool, even in 1 sentence, would be helpful.
parttimenerd 3y ago
Thanks for the feedback, I added a small disclaimer at the beginning of the article, telling the reader what JFR is and where to find more information.
- 3y ago

xcdzvyn 3y ago

The Minecraft Wiki community is moving away from Fandom to the self-hosted https://minecraft.wiki/ https://minecraft.wiki/. Could you update your article to reflect that, by any chance? Edit: Wow! You've never played Minecraft before? That's crazy!

parttimenerd 3y ago
Thanks, I fixed it. > Edit: Wow! You've never played Minecraft before? That's crazy! I don't play computer games (the last game I played was "Thomas was alone"), but I know people that play it more often. Edit: Link to the game https://de.wikipedia.org/wiki/Thomas_Was_Alone https://de.wikipedia.org/wiki/Thomas_Was_Alone. Nowadays, I like to play whack-a-mole with bugs in the OpenJDK.
- xcdzvyn 3y ago
  Thanks! And thank you for your work :)
  - parttimenerd 3y ago
    I'm happy for any reader of my blog :)