8355798: Implement JEP 514: Ahead-of-Time Command Line Ergonomics #24942

iklam · 2025-04-29T04:50:42Z

This is the implementation of the draft JEP: Ahead-of-time Command Line Ergonomics

Implemented new flag AOTCacheOutput, which can be used to create an AOT cache using the "one-command workflow"
Added processing of the JDK_AOT_VM_OPTIONS environment variable that can supply extra VM options when creating an AOT cache
Added %p substitution for AOTCache, AOTCacheOutput, and AOTConfiguration options

Please see the JEP and CSR for detailed specification.

Examples:

# Create an AOT cache with a single command:
$ java -cp HelloWorld.jar -XX:AOTMode=record -XX:AOTCacheOutput=foo.aot HelloWorld
Hello World
Temporary AOTConfiguration recorded: foo.aot.config
Launching child process /usr/bin/java to assemble AOT cache foo.aot using configuration foo.aot.config
[...]
Reading AOTConfiguration foo.aot.config and writing AOTCache foo.aot
AOTCache creation is complete: foo.aot 10240000 bytes

# Create logging file for the AOT cache assembly phase
$ export AOT_TOOL_COMMAND=-Xlog:cds:file=log.txt
$ java -cp HelloWorld.jar -XX:AOTMode=record -XX:AOTCacheOutput=foo.aot HelloWorld

Note: the child process is launched with Java API because the HotSpot native APIs are not sufficient (no way to set env vars for child process).

Progress

Change must be properly reviewed (1 review required, with at least 1 Reviewer)
Change must not contain extraneous whitespace
Change requires CSR request JDK-8356010 to be approved
Commit message must refer to an issue

Issues

JDK-8355798: Implement JEP 514: Ahead-of-Time Command Line Ergonomics (Sub-task - P4)
JDK-8356010: Implement JEP 514: Ahead-of-Time Command Line Ergonomics (CSR)

Reviewers

Vladimir Kozlov (@vnkozlov - Reviewer) Review applies to 7f4c0e8b
Ashutosh Mehra (@ashu-mehra - Committer) Review applies to 5004a0b7
Erik Joelsson (@erikj79 - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/24942/head:pull/24942
$ git checkout pull/24942

Update a local copy of the PR:
$ git checkout pull/24942
$ git pull https://git.openjdk.org/jdk.git pull/24942/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 24942

View PR using the GUI difftool:
$ git pr show -t 24942

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/24942.diff

Using Webrev

Link to Webrev Comment

…mics

bridgekeeper · 2025-04-29T04:51:12Z

👋 Welcome back iklam! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2025-04-29T04:51:36Z

@iklam This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8355798: Implement JEP 514: Ahead-of-Time Command Line Ergonomics

Reviewed-by: erikj, kvn, asmehra

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

openjdk · 2025-04-29T04:52:08Z

@iklam The following labels will be automatically applied to this pull request:

core-libs
hotspot-runtime

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

vnkozlov · 2025-04-29T15:48:12Z

JEP and CSR call env var :JAVA_AOT_OPTIONS. This description and changes call it AOT_TOOL_OPTIONS. Please, fix.

vnkozlov

Few comments.

src/hotspot/share/cds/metaspaceShared.cpp

src/java.base/share/classes/jdk/internal/misc/CDS.java

openjdk · 2025-05-01T21:04:27Z

@iklam this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout 8355798-implement-leyden-ergo-jep-8350022
git fetch https://git.openjdk.org/jdk.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

mlbridge · 2025-05-05T00:29:18Z

Webrevs

iklam · 2025-05-05T00:57:00Z

JEP and CSR call env var :JAVA_AOT_OPTIONS. This description and changes call it AOT_TOOL_OPTIONS. Please, fix.

Fixed.

src/hotspot/share/cds/metaspaceShared.cpp

src/hotspot/share/cds/cdsConfig.cpp

vnkozlov

Good.

vnkozlov

Few comments.

vnkozlov · 2025-05-14T15:38:06Z

src/hotspot/share/cds/cds_globals.hpp

+          "Write AOT cache into this file (overrides AOTCache when "        \
+          "writing)")                                                       \


This looks not complete description. And "override AOTCache .." is confusing.

I changed it to "Specifies the file name for writing the AOT cache". Since the behavior is complex, I don't know how much detail I should put here.

vnkozlov · 2025-05-14T15:51:31Z

src/hotspot/share/cds/metaspaceShared.cpp

+  stringStream ss;
+  print_java_launcher(&ss);
+  const char* cmd = ss.freeze();
+  tty->print_cr("Launching child process %s to assemble AOT cache %s using configuration %s", cmd, AOTCacheOutput, AOTConfiguration);


I noticed that AOT produces outputs on TTY like this unconditionally. I think it is fine for development but for production we should use UL I think.
Was this discussed?

Currently we print things that are important to the user. The other examples are:

$ java -XX:AOTMode=record .... AOTConfiguration recorded: hw.aotconfig $ java -XX:AOTMode=create .... Reading AOTConfiguration hw.aotconfig and writing AOTCache hw.aot AOTCache creation is complete: hw.aot 10498048 bytes

I think AOT is still a new feature so a small number of TTY prints would be helpful. If people complain about the verbosity we can change them to UL logs.

vnkozlov · 2025-05-14T15:54:37Z

src/hotspot/share/runtime/arguments.cpp

  return parse_options_environment_variable("JAVA_TOOL_OPTIONS", args);
 }

+static JavaVMOption* get_last_aotmode_arg(const JavaVMInitArgs* args) {


I don't like that we pollute Arguments code with AOT specific flags processing.
Can we move this into CDSConfig? Both these 2 new methods.

But I will agree if you want to keep it here. It is not critical.

These two functions are for parsing JDK_AOT_VM_OPTIONS, so I think they belong to arguments.cpp. cdsConfig.cpp is a consumer of the options parsed by arguments.cpp.

vnkozlov · 2025-05-14T15:58:57Z

src/java.base/share/man/java.md

       mode should be used only as a "fail-fast" debugging aid to check if your command-line
       options are compatible with the AOT cache. An alternative is to run your application with
-       `-XX:AOTMode=auto -Xlog:cds` to see if the AOT cache can be used or not.
+       `-XX:AOTMode=auto -Xlog:cds,aot` to see if the AOT cache can be used or not.


-Xlog:aot

-Xlog:cds,aot is correct for the current state of this PR. I'll change it after JDK-8356595 is integrated into the mainline.

vnkozlov · 2025-05-14T16:01:36Z

test/hotspot/jtreg/runtime/cds/appcds/aotFlags/AOTFlags.java

+            "-XX:AOTMode=record",
+            "-XX:-AOTClassLinking",
+            "-XX:AOTConfiguration=" + aotConfigFile,
+            "-Xlog:cds=debug",


-Xlog:aot
I assume JDK-8356595: "Convert -Xlog:cds to -Xlog:aot " will be pushed first.

-Xlog:cds=debug is correct for the current state of this PR (otherwise the test will fail). I'll change it after JDK-8356595 is integrated into the mainline.

vnkozlov

Looks good.

erikj79 · 2025-05-15T12:59:12Z

doc/testing.md

+One way to improve test coverage of ahead-of-time (AOT) optimizations in the JDK is to
+run existing jtreg test cases in a special "AOT_JDK" mode. Example:
+
+


Is this extra newline intentional?

erikj79 · 2025-05-15T13:01:08Z

doc/testing.md

+
+Also, test cases that were written specifically to test AOT, such as the tests
+under [test/hotspot/jtreg/runtime/cds](../test/hotspot/jtreg/runtime/cds/), cannot
+be execute with the AOT_JDK mode.


Suggested change

be execute with the AOT_JDK mode.

be executed with the AOT_JDK mode.

erikj79 · 2025-05-15T13:01:48Z

doc/testing.md

+under [test/hotspot/jtreg/runtime/cds](../test/hotspot/jtreg/runtime/cds/), cannot
+be execute with the AOT_JDK mode.
+
+Valid values for `AOT_JDK` are `one_step` and `two_step`. These control how


Looks like the values are onestep and twostep in the makefile.

erikj79 · 2025-05-15T13:03:24Z

doc/testing.md

+In this testing mode, we first perform an AOT training run (see https://openjdk.org/jeps/483)
+of a special test program ([test/setup_aot/TestSetupAOT.java](../test/setup_aot/TestSetupAOT.java))
+that accesses about 5,0000 classes in the JDK core libraries. Optimization artifacts for
+these classes (such as pre-linked lambda expressions, execution profiles, and pre-generated native code)
+are stored into an AOT cache file, which will be used by all the JVMs launched by the selected jtreg
+test cases.


Some of these lines are >80 chars. Can you try to format line lengths in this file to stay under where reasonably feasible? It's ok if long markups such as links go over, just try to keep the normal text adhering to this.

erikj79 · 2025-05-20T19:48:06Z

make/RunTests.gmk

  $$($1_AOT_JDK_CACHE): $$(JDK_IMAGE_DIR)/release
 	$$(call MakeDir, $$($1_AOT_JDK_OUTPUT_DIR))

+  ifeq ($$($1_TRAINING), onestep)


Sorry for not noticing this earlier. This is a conditional within a recipe. The preferred style for those are to align the ifeq, else and endif with the recipe itself, using spaces (as it's not a recipe line), and then indent the body with 2 extra spaces for logical indentation. See points 5 and 6 in https://openjdk.org/groups/build/doc/code-conventions.html. You can find an example of this in make/Bundles.gmk.

iklam · 2025-05-28T22:08:46Z

/integrate

openjdk · 2025-05-28T22:12:14Z

Going to push as commit dede353.
Since your change was applied there have been 4 commits pushed to the master branch:

b7f0f48: 8357681: Fixed the DigitList::toString method causing incorrect results during debugging
bb2c80c: 8298420: Implement JEP 470: PEM Encodings of Cryptographic Objects (Preview)
28f5093: 8356233: NMT: tty->print_cr should not be used in VirtualMemoryTracker::add_reserved_region()
... and 1 more: https://git.openjdk.org/jdk/compare/b2a61a9972493d67d0f1a9f3f529c11e45838d5b...master

Your commit was automatically rebased without conflicts.

openjdk · 2025-05-28T22:12:21Z

@iklam Pushed as commit dede353.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

8355798: Implement JEP-JDK-8350022: Ahead-of-time Command Line Ergono…

874f866

…mics

openjdk bot added hotspot-runtime hotspot-runtime-dev@openjdk.org core-libs core-libs-dev@openjdk.org labels Apr 29, 2025

iklam added 2 commits April 28, 2025 23:57

Refactored code to enfore the order of argument parsing

6b0191c

added comment that was removed in previous commit

b9ebd92

vnkozlov reviewed Apr 29, 2025

View reviewed changes

src/hotspot/share/cds/metaspaceShared.cpp Show resolved Hide resolved

src/hotspot/share/cds/metaspaceShared.cpp Outdated Show resolved Hide resolved

src/java.base/share/classes/jdk/internal/misc/CDS.java Show resolved Hide resolved

openjdk bot added the csr Pull request needs approved CSR before integration label Apr 30, 2025

openjdk bot added the merge-conflict Pull request has merge conflict with target branch label May 1, 2025

iklam changed the title ~~8355798: Implement JEP-JDK-8350022: Ahead-of-time Command Line Ergonomics~~ 8355798: Implement JEP-512: Ahead-of-Time Command Line Ergonomics May 4, 2025

iklam changed the title ~~8355798: Implement JEP-512: Ahead-of-Time Command Line Ergonomics~~ 8355798: Implement JEP-514: Ahead-of-Time Command Line Ergonomics May 4, 2025

iklam changed the title ~~8355798: Implement JEP-514: Ahead-of-Time Command Line Ergonomics~~ 8355798: Implement JEP 514: Ahead-of-Time Command Line Ergonomics May 4, 2025

iklam added 4 commits May 3, 2025 21:30

fixed typo

9f70868

Merge branch 'master' into 8355798-implement-leyden-ergo-jep-8350022

0416487

Added %p substitution; clean up

2bdb005

Remove %t restriction

acba394

openjdk bot removed the merge-conflict Pull request has merge conflict with target branch label May 4, 2025

iklam marked this pull request as ready for review May 5, 2025 00:24

openjdk bot added the rfr Pull request is ready for review label May 5, 2025

iklam added 2 commits May 4, 2025 17:34

AOT_TOOL_OPTIONS -> JAVA_AOT_OPTIONS

5e51e8f

@vnkozlov comments

0eb8b54

vnkozlov reviewed May 5, 2025

View reviewed changes

src/hotspot/share/cds/metaspaceShared.cpp Show resolved Hide resolved

vnkozlov reviewed May 5, 2025

View reviewed changes

src/hotspot/share/cds/cdsConfig.cpp Show resolved Hide resolved

vnkozlov approved these changes May 6, 2025

View reviewed changes

iklam added 2 commits May 13, 2025 23:01

Resolved differences with CSR JDK-8356010

f468ae5

java.md updates from @rose00

cd7a5a6

vnkozlov reviewed May 14, 2025

View reviewed changes

iklam added 4 commits May 14, 2025 16:39

Merge branch 'master' into 8355798-implement-leyden-ergo-jep-8350022

7b8ad9b

fixed whitespace

d8d6e1f

added info about JTREG/AOT_JDK testing

9ab4166

@vnkozlov comments

7f4c0e8

openjdk bot added the rfr Pull request is ready for review label May 15, 2025

vnkozlov approved these changes May 15, 2025

View reviewed changes

erikj79 reviewed May 15, 2025

View reviewed changes

openjdk bot added ready Pull request is ready to be integrated and removed csr Pull request needs approved CSR before integration labels May 19, 2025

iklam added 2 commits May 19, 2025 18:38

Merge branch 'master' into 8355798-implement-leyden-ergo-jep-8350022

3347921

@erikj79 comments

0956fca

openjdk bot removed the ready Pull request is ready to be integrated label May 20, 2025

Fixed merge

502d1c0

erikj79 reviewed May 20, 2025

View reviewed changes

iklam added 3 commits May 22, 2025 14:34

@erikj79 comments -- makefile indentation

f3ffe34

Merge branch 'master' into 8355798-implement-leyden-ergo-jep-8350022

9a18864

Fixed merge

de16fdb

erikj79 approved these changes May 23, 2025

View reviewed changes

openjdk bot added the ready Pull request is ready to be integrated label May 23, 2025

Merge branch 'master' into 8355798-implement-leyden-ergo-jep-8350022

a8ce491

openjdk bot added the integrated Pull request has been integrated label May 28, 2025

openjdk bot closed this May 28, 2025

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels May 28, 2025

		"Write AOT cache into this file (overrides AOTCache when " \
		"writing)") \

		One way to improve test coverage of ahead-of-time (AOT) optimizations in the JDK is to
		run existing jtreg test cases in a special "AOT_JDK" mode. Example:

	be execute with the AOT_JDK mode.
	be executed with the AOT_JDK mode.

8355798: Implement JEP 514: Ahead-of-Time Command Line Ergonomics #24942

8355798: Implement JEP 514: Ahead-of-Time Command Line Ergonomics #24942

Uh oh!

Conversation

iklam commented Apr 29, 2025 • edited by openjdk bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Progress

Issues

Reviewers

Reviewing

Uh oh!

bridgekeeper bot commented Apr 29, 2025

Uh oh!

openjdk bot commented Apr 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

openjdk bot commented Apr 29, 2025

Uh oh!

vnkozlov commented Apr 29, 2025

Uh oh!

vnkozlov left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

openjdk bot commented May 1, 2025

Uh oh!

mlbridge bot commented May 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Webrevs

Uh oh!

iklam commented May 5, 2025

Uh oh!

Uh oh!

Uh oh!

vnkozlov left a comment

Choose a reason for hiding this comment

Uh oh!

vnkozlov left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

vnkozlov left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

iklam commented May 28, 2025

Uh oh!

openjdk bot commented May 28, 2025

iklam commented Apr 29, 2025 •

edited by openjdk bot

Loading

openjdk bot commented Apr 29, 2025 •

edited

Loading

mlbridge bot commented May 5, 2025 •

edited

Loading