On Mon, 1 Jun 2026 21:58:42 GMT, Ioi Lam <[email protected]> wrote: > Before this PR, you cannot use -XX:AOTCache in the training run: > > > $ java -XX:AOTCache=foo.aot -cp HelloWorld.jar \ > -XX:AOTMode=record -XX:AOTConfiguration=hw.aotconfig \ > HelloWorld > [...] AOTCache must not be specified when using -XX:AOTMode=record > > > However, in some cases, it may be desirable to train the AOT cache in two or > more steps. For example: > > ## Separate Training for Framework and Application: > > - First perform a training run to exercise commonly-used areas of the > framework. > - Second, perform a training run of a specific application. > > The idea is that important parts of the framework may not be covered by a > single application training run, but they may still be used in the production > run due to runtime-specific input. > > > # Train the framework > java -XX:AOTCacheOutput=first.aot -cp FrameWork.jar FrameWorkTraningHelper > > # Train the app > java -XX:AOTCache=first.aot -XX:AOTCacheOutput=second.aot -cp > FrameWork.jar:App.jar MyApp > > # Production run using second.aot, which contains artifacts from > # the first and second training runs > java -XX:AOTCache=second.aot -cp FrameWork.jar:App.jar MyApp > > Note that the classpaths of the training runs must be compatible. I.e., the > classpath of an earlier training run must be the same as, or the prefix of, > the classpath of a later training run. > > ## Train the Same Application in Multiple Runs: > > An application may perform 3 different operations. It's not easy to perform > all 3 operations in a single training run, as the 3 operations are > represented by 3 separate main classes (`WalkDog`, `FeedCat`, and > `WaterPlants`). So, we perform 3 separate training runs and combine the > results into a single AOT cache. > > > # Training > java -XX:AOTCacheOutput=tmp1.aot -cp MyApp.jar WalkDog > java -XX:AOTCache=tmp1.aot -XX:AOTCacheOutput=tmp2.aot -cp MyApp.jar FeedCat > java -XX:AOTCache=tmp2.aot -XX:AOTCacheOutput=final.aot -cp MyApp.jar > WaterPlants > > # Production: final.aot contains artifacts for optimizing all 3 operations: > java -XX:AOTCache=final.aot -cp MyApp.jar WalkDog > java -XX:AOTCache=final.aot -cp MyApp.jar FeedCat > java -XX:AOTCache=final.aot -cp MyApp.jar WaterPlants > > > --------- > - [x] I confirm that I make this contribution in accordance with the [OpenJDK > Interim AI Policy](https://openjdk.org/legal/ai).
Marked as reviewed by iveresov (Reviewer). ------------- PR Review: https://git.openjdk.org/jdk/pull/31344#pullrequestreview-5589323922
