7451: Add heat map view

[cimi]

This PR adds a new plugin (flightrecorder.heatmap) which renders a visualisation similar to the one in this Observable notebook.

The code is simpler than both the flame view and the graph view, because of less rendering options and less dependencies - the heatmap only requires d3 and currently does not support any user configuration.

Each cell represents 100 milliseconds from the recording. We decided to automatically adjust the size of the cell so that the entire heatmap fits inside the window. This is different from the observable notebook which ensured each row represented 6s (i.e. it had a fixed number of 60 columns). The auto-sizing seems to work well with both small and large recordings, although we lose consistency when we resize the window and some periodic patterns are no longer visible when we vary the number of columns.

Feedback welcome, here's how this looks now:

(short recording - 2 min)

(long recording - 15 min)

---

Progress

• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JMC-7451: Add heat map view

Reviewers

• Marcus Hirt (@thegreystone - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jmc pull/337/head:pull/337
$ git checkout pull/337

Update a local copy of the PR:
$ git checkout pull/337
$ git pull https://git.openjdk.java.net/jmc pull/337/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 337

View PR using the GUI difftool:
$ git pr show -t 337

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jmc/pull/337.diff

[bridgekeeper]

👋 Welcome back cimi! 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.

[mlbridge]

Webrevs

• 03: Full - Incremental (7ad43eed)
• 02: Full (768ec2a0)
• 01: Full - Incremental (f6286af5)
• 00: Full (3c71b4b2)

[openjdk]

@cimi 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 cimi/heatmap
git fetch https://git.openjdk.java.net/jmc master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[thegreystone]

This looks great! :)

[openjdk]

@cimi 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:

7451: Add heat map view

Reviewed-by: hirt

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 3 new commits pushed to the master branch:

• 787bf0a: 7456: Remove the JDK 8 Eclipse launchers
• 8b8aa7c: 7463: JfrEditor instances are kept in memory by NavigationHistory
• d4449ce: 7439: Introduced IConstantPoolExtension for Constant Pools

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@thegreystone) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[thegreystone]

@cimi - this one is ready for /integrate.

[cimi]

/integrate

[openjdk]

@cimi
Your change (at version 7ad43ee) is now ready to be sponsored by a Committer.

[thegreystone]

/sponsor

[openjdk]

Going to push as commit ba365fb.
Since your change was applied there have been 3 commits pushed to the master branch:

• 787bf0a: 7456: Remove the JDK 8 Eclipse launchers
• 8b8aa7c: 7463: JfrEditor instances are kept in memory by NavigationHistory
• d4449ce: 7439: Introduced IConstantPoolExtension for Constant Pools

Your commit was automatically rebased without conflicts.

[openjdk]

@thegreystone @cimi Pushed as commit ba365fb.

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