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I'm still struggling to learn what patches exactly Amazon put in their OpenJDK build. Does anyone know how to get access to these details?

papercrane 5y ago
They maintain a page for each version listing patches. I don't believe it's up for 18 yet, but given the short list for 17 I expect it's currently just patching the vendor metadata. https://docs.aws.amazon.com/corretto/latest/corretto-8-ug/patches.html https://docs.aws.amazon.com/corretto/latest/corretto-8-ug/pa... https://docs.aws.amazon.com/corretto/latest/corretto-11-ug/patches.html https://docs.aws.amazon.com/corretto/latest/corretto-11-ug/p... https://docs.aws.amazon.com/corretto/latest/corretto-17-ug/patches.html https://docs.aws.amazon.com/corretto/latest/corretto-17-ug/p... Edit: While not technically a patch, I should note that they do have different compile options than the Oracle builds. The biggest difference I can think of is Amazon ships with the Shenandoah GC enabled, while Oracle's builds do not.
- belter 5y ago
  I prefer to look here, nothing yet for 18... Change Log for Amazon Corretto 17 https://github.com/corretto/corretto-17/blob/develop/CHANGELOG.md https://github.com/corretto/corretto-17/blob/develop/CHANGEL... Change Log for Amazon Corretto 18 https://github.com/corretto/corretto-18/blob/develop/CHANGELOG.md https://github.com/corretto/corretto-18/blob/develop/CHANGEL...
otterley 5y ago
One patch (back in Corretto 11) relates to arm64, the CPU architecture that their Graviton EC2 instances (m6g/r6g/c6g/etc) use. It significantly reduces lock-related context-switch overhead and improves performance of high-concurrency Java applications as a result. Replacing OpenJDK 11 with Corretto can reduce CPU utilization of Kafka brokers on that platform by up to 20%.
- bitcharmer 5y ago
  That's nice but where can I read about it?
  - papercrane 5y ago
    That fix is in mainline OpenJDK, so it's not included in their list of patches. I found it by looking at their changelog for Corretto 11, which includes both their patches and the changes from mainline. https://github.com/corretto/corretto-11/blob/develop/CHANGELOG.md https://github.com/corretto/corretto-11/blob/develop/CHANGEL... https://bugs.openjdk.java.net/browse/JDK-8186670 https://bugs.openjdk.java.net/browse/JDK-8186670
    - otterley 5y ago
      Thanks. I updated my comment to clarify that this is about OpenJDK 11; later versions of OpenJDK apparently already include this patch.

papercrane 5y ago

They maintain a page for each version listing patches. I don't believe it's up for 18 yet, but given the short list for 17 I expect it's currently just patching the vendor metadata. https://docs.aws.amazon.com/corretto/latest/corretto-8-ug/patches.html https://docs.aws.amazon.com/corretto/latest/corretto-8-ug/pa... https://docs.aws.amazon.com/corretto/latest/corretto-11-ug/patches.html https://docs.aws.amazon.com/corretto/latest/corretto-11-ug/p... https://docs.aws.amazon.com/corretto/latest/corretto-17-ug/patches.html https://docs.aws.amazon.com/corretto/latest/corretto-17-ug/p... Edit: While not technically a patch, I should note that they do have different compile options than the Oracle builds. The biggest difference I can think of is Amazon ships with the Shenandoah GC enabled, while Oracle's builds do not.

belter 5y ago
I prefer to look here, nothing yet for 18... Change Log for Amazon Corretto 17 https://github.com/corretto/corretto-17/blob/develop/CHANGELOG.md https://github.com/corretto/corretto-17/blob/develop/CHANGEL... Change Log for Amazon Corretto 18 https://github.com/corretto/corretto-18/blob/develop/CHANGELOG.md https://github.com/corretto/corretto-18/blob/develop/CHANGEL...

otterley 5y ago

One patch (back in Corretto 11) relates to arm64, the CPU architecture that their Graviton EC2 instances (m6g/r6g/c6g/etc) use. It significantly reduces lock-related context-switch overhead and improves performance of high-concurrency Java applications as a result. Replacing OpenJDK 11 with Corretto can reduce CPU utilization of Kafka brokers on that platform by up to 20%.

bitcharmer 5y ago
That's nice but where can I read about it?
- papercrane 5y ago
  That fix is in mainline OpenJDK, so it's not included in their list of patches. I found it by looking at their changelog for Corretto 11, which includes both their patches and the changes from mainline. https://github.com/corretto/corretto-11/blob/develop/CHANGELOG.md https://github.com/corretto/corretto-11/blob/develop/CHANGEL... https://bugs.openjdk.java.net/browse/JDK-8186670 https://bugs.openjdk.java.net/browse/JDK-8186670
  - otterley 5y ago
    Thanks. I updated my comment to clarify that this is about OpenJDK 11; later versions of OpenJDK apparently already include this patch.