8361640: JFR: RandomAccessFile::readLine emits events for each character

[egahlin]

Could I have a review of the change that prevents RandomAccessFile::readLine from emitting an event per character? This leads to unnecessary overhead, both with or without JFR enabled.

Testing: tier1 + tier2 + jdk/jdk/jfr

Thanks
Erik

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8361640: JFR: RandomAccessFile::readLine emits events for each character (Bug - P3)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/26210/head:pull/26210
$ git checkout pull/26210

Update a local copy of the PR:
$ git checkout pull/26210
$ git pull https://git.openjdk.org/jdk.git pull/26210/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 26210

View PR using the GUI difftool:
$ git pr show -t 26210

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/26210.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back egahlin! 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]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

@egahlin The following label will be automatically applied to this pull request:

• core-libs

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

[egahlin]

/label add hotspot-jfr

[openjdk]

@egahlin
The hotspot-jfr label was successfully added.

[mlbridge]

Webrevs

• 00: Full (027093ed)

[AlanBateman]

Testing: tier1 + jdk/jdk/jfr

The tests for this area are in tier2 (not tier1).

[AlanBateman]

I think we'll need to see if a test can be added as it's way too easy to refactor this code and re-introduce the issue.

[egahlin]

I think we'll need to see if a test can be added as it's way too easy to refactor this code and re-introduce the issue.

I'm planning a follow-up PR that will check the top frame. Here's the draft:
#26211

That test will count the number of events also, so it can detect if the code is refactored.

[egahlin]

Testing: tier1 + jdk/jdk/jfr

The tests for this area are in tier2 (not tier1).

I ran tier2. It was fine.