JDK-8232090 : Turn off AOT by default
  • Type: CSR
  • Component: hotspot
  • Sub-Component: compiler
  • Priority: P3
  • Status: Closed
  • Resolution: Approved
  • Fix Versions: 11.0.6-oracle
  • Submitted: 2019-10-10
  • Updated: 2019-11-15
  • Resolved: 2019-10-17
Related Reports
CSR :  
JDK-8234255 - Turn off AOT by default
CSR :  
JDK-8230427 - Turn off AOT by default
Relates :  
JDK-8227833 - Turn off AOT by default
Description
Summary
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Turn off AOT by default and make related flags experimental to reflect that JEP 295 AOT is still experimental.

Problem
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The AOT feature is experimental, which implies it should not have any impact for users not interested in or unaware of the same. At present the related command line options `UseAOT`, `AOTLibrary`, and `PrintAOT` are product flags and `UseAOT` is enabled by default, which leads it can have a performance impact.

Solution
--------

 - Change the related flags `UseAOT`, `PrintAOT`, and `AOTLibrary` to experimental type.
 - Turn off `UseAOT` by default.

Specification
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The following flags are made experimental in JDK 11u: `UseAOT`, `PrintAOT`, and `AOTLibrary`. Default value of `UseAOT` is changed from enabled to disabled.
Comments
On a procedural note, backporting a fix with a CSR in a feature release, say 14, into an update release, say 11.0.x does require separate CSR review. There are many cases where a fix that is fine in a feature release is inappropriate for an update release. FYI, the situation of this CSR is discussed in the CSR FAQ: Q: How should I get CSR review for multiple release trains? A: Say you want to get an interface change into JDK N and later decide the change is also desirable and appropriate for the JDK (N-1) update release and that update release is using the CSR process. First a CSR should be created from the main bug targeted at JDK N. Afterward, if a backport of the main bug covering JDK (N-1) does not already exist, a backport of the main bug covering JDK (N-1) should be created. Then, a CSR can be created from that backport. https://wiki.openjdk.java.net/display/csr/CSR+FAQs As previous noted in the CSR for the main issue, IMO these changes merit a release note. please write one. Moving to Approved.
17-10-2019
Moving to Finalized. (Please note the related 11u release note backport is handled in JDK-8232221. But please let me know if this 11u specific CSR is not needed or If something is missing here. Thanks.)
16-10-2019
Do we really need new CSR for 11u? We ahve approved one JDK-8227833 for JDK 14.
10-10-2019
Please note the Original issue JDK-8227439 was committed in JDK 14 after getting the required CSR approval (JDK-8227833). But unfortunately I missed the CSR request, approval process before the commit of the jdk11u-cpu - backport of the same task. So now creating this new CSR for the same. I hope reverting of the jdk11u-cpu - backport commit is not required before completing this CSR process. Hi [~kvn], [~redestad], please review this draft CSR. Can this be moved to 'Finalized' for final review? Please let me know if I am missing something here. Thanks,
10-10-2019