JDK-8316448 : [JVMCI] Do not load jdk.internal.vm.ci automatically if UseJVMCINativeLibrary is true
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 22
  • Priority: P4
  • Status: Closed
  • Resolution: Withdrawn
  • Submitted: 2023-09-18
  • Updated: 2024-06-21
  • Resolved: 2023-09-27
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tbdResolved
Related Reports
Relates :  
JDK-8266329 - Improve CDS module graph support for command-line options
Description
A consequence of JDK-8266329 is that -Xcomp on libgraal does a lot more class loading and therefore a lot more compilation during VM startup than C2.

The reason is that EnableJVMCI automatically adds the jdk.internal.vm.ci module which disables the CDS archived full module graph (FMG). Without FMG, a lot of core JDK classes must be loaded instead being read from the archive.

In the context of libgraal, there's never a need to load jdk.internal.vm.ci - it is already AOT compiled into libgraal. In local measurements on an empty main program with -Xcomp and a fastdebug build of libgraal, avoiding loading of jdk.internal.vm.ci and thus being able to use the FMG reduces execution time from 38 secs to 9 secs.
Comments
Withdrawn - see https://bugs.openjdk.org/browse/JDK-8266329?focusedCommentId=14613585&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14613585.
27-09-2023