Virtual Threads - Project Loom support

cbridgha commented 1 year ago

Description

In addition to our normal JDK level 21 support, This feature will cover our internal changes taking advantage of Virtual Threads, (Primarily around our Executor service, and options to create VirtualThreads, instead of our normal platform threads through our managed thread pool). considerations to our customers expecting to use VT and expectation of our Executor's providing VT support.

Prototyping from the performance team is ongoing and findings will be feeding into recommendations for exploitation.

This also includes synchronization issues that could prevent users taking advantage.

Official JEP included for Java 21: https://openjdk.org/jeps/444

Documents

When available, add links to required feature documents. Use "N/A" to mark particular documents which are not required by the feature.

Aha: Externally raised RFE (Aha)
- Link the RFE with this issue
UFO: Link to VT UFO
FTS: Link to Feature Test Summary GH Issue
Beta Blog: Link to Beta Blog Post GH Issue
GA Blog: Link to GA Blog Post GH Issue
Process Overview
Prioritization
Design
Implementation
Legal and Translation
Beta
GA
- Focal Point Approvals
Other Deliverables

General Instructions

The process steps occur roughly in the order as presented. Process steps occasionally overlap.

Each process step has a number of tasks which must be completed or must be marked as not applicable ("N/A").

Unless otherwise indicated, the tasks are the responsibility of the Feature Owner or a Delegate of the Feature Owner.

If you need assistance, reach out to the OpenLiberty/release-architect.

Important: Labels are used to trigger particular steps and must be added as indicated.

Prioritization (Complete Before Development Starts)

The (OpenLiberty/chief-architect) and area leads are responsible for prioritizing the features and determining which features are being actively worked on.

Prioritization

[ ] Feature added to the "New" column of the Open Liberty project board
- Epics can be added to the board in one of two ways:
- From this issue, use the "Projects" section to select the appropriate project board.
- From the appropriate project board click "Add card" and select your Feature Epic issue
[ ] Priority assigned
- Attend the Liberty Backlog Prioritization meeting
Design (Complete Before Development Starts)

Design preliminaries determine whether a formal design, which will be provided by an Upcoming Feature Overview (UFO) document, must be created and reviewed. A formal design is required if the feature requires any of the following: UI, Serviceability, SVT, Performance testing, or non-trivial documentation/ID.

Design Preliminaries

[ ] UI requirements identified. (Owner and UI focal point)
[ ] ID requirements identified. (Owner and ID focal point)
- Refer to Documenting Open Liberty.
- Feature Owner adds label ID Required, if non-trivial documentation needs to be created by the ID team.
- ID adds label ID Required - Trivial, if no design will be performed and only trivial ID updates are needed.
[ ] Serviceability Requirements Identified. (Owner and Serviceability focal point)
[ ] SVT Requirements Identified. (Owner and SVT focal point)
[ ] Performance testing requirements identified. (Owner and Performance focal point)

Design

[ ] POC Design / UFO review requested.
- Owner adds label Design Review Request
[ ] POC Design / UFO review scheduled.
- Follow the instructions in POC-Forum repo
[ ] POC Design / UFO review completed.
[ ] POC / UFO Review follow-ons completed.
[ ] POC Design / UFO approval requested.
- Owner adds label Design Approval Request
[ ] Design / UFO approved. (OpenLiberty/chief-architect) or N/A
- (OpenLiberty/chief-architect) adds label Design Approved
- Add the public link to the UFO in Box to the Documents section.
- The UFO must always accurately reflect the final implementation of the feature. Any changes must be first approved. Afterwards, update the UFO by creating a copy of the original approved slide(s) at the end of the deck and prepend "OLD" to the title(s). A single updated copy of the slide(s) should take the original's place, and have its title(s) prepended with "UPDATED".

No Design

[ ] No Design requested.
- Owner adds label No Design Approval Request
[ ] No Design / No UFO approved. (OpenLiberty/chief-architect) or N/A
- Approver adds label No Design Approved
[ ] Feature / Capability stabilization or discontinuation or N/A
- Owner adds label Product Management Approval Request and notifies OpenLiberty/product-management
- Approver adds label Product Management Approved (OpenLiberty/product-management)
- Note: For stabilized, superseded, and discontinued feature/capability, skip the Beta section of the template (you may delete it). Otherwise, proceed as normal.

FAT Documentation

[ ] "Feature Test Summary" child task created
- Use the Feature Test Summary Template
- Add FTS issue link to the Documents section.
Implementation

A feature must be prioritized before any implementation work may begin to be delivered (inaccessible/no-ship). However, a design focused approach should still be applied to features, and developers should think about the feature design prior to writing and delivering any code.
Besides being prioritized, a feature must also be socialized (or No Design Approved) before any beta code may be delivered. All new Liberty content must be inaccessible in our GA releases until it is Feature Complete by either marking it kind=noship or beta fencing it.
Code may not GA until this feature has obtained the "Design Approved" or "No Design Approved" label, along with all other tasks outlined in the GA section.

Feature Development Begins

[ ] Add the In Progress label

Legal and Translation

In order to avoid last minute blockers and significant disruptions to the feature, the legal items need to be done as early in the feature process as possible, either in design or as early into the development as possible. Similarly, translation is to be done concurrently with development. Both MUST be completed before Beta or GA is requested.

Legal (Complete before Feature Complete Date)

[ ] Changed or new open source libraries are cleared and approved, or N/A. (Legal Release Services/Cass Tucker/Release PM).
[ ] Licenses and Certificates of Originality (COOs) are updated, or N/A

Translation (Complete 1 week before Feature Complete Date)

[ ] PII updates are merged, or N/A. Note timing with translation shipments.

Innovation (Complete 1 week before Feature Complete Date)

[ ] Consider whether any aspects of the feature may be patentable. If any identified, disclosures have been submitted.
Beta

In order to facilitate early feedback from users, all new features and functionality should first be released as part of a beta release.

Beta Code

[ ] Beta fence the functionality
- kind=beta, ibm:beta, ProductInfo.getBetaEdition()
[ ] Beta development complete and feature ready for inclusion in a beta release
- Add label target:beta and the appropriate target:YY00X-beta (where YY00X is the targeted beta version).
[ ] Feature delivered into beta
- (OpenLiberty/release-manager) adds label release:YY00X-beta (where YY00X is the first beta version that included the functionality).

Beta Blog (Complete 1.5 weeks before beta eGA)

[ ] Beta blog issue created and populated using the Open Liberty BETA blog post template.
- Add a link to the beta blog issue in the Documents section.
- Note: This is for inclusion into the overall beta release blog post. If, in addition, you'd also like to create a dedicated blog post about your feature, then follow the "Standalone Feature Blog Post" instructions under the Other Deliverables section.
GA

A feature is ready to GA after it is Feature Complete and has obtained all necessary Focal Point Approvals.

Feature Complete

[ ] Feature implementation and tests completed.
- [ ] All PRs are merged.
- [ ] All epic and child issues are closed.
- [ ] All stop ship issues are completed.
[ ] Legal: all necessary approvals granted.
[ ] Translation: All messages translated or sent for translation for upcoming release
[ ] GA development complete and feature ready for inclusion in a GA release
- Add label target:ga and the appropriate target:YY00X (where YY00X is the targeted GA version).
- Inclusion in a release requires the completion of all Focal Point Approvals.

Focal Point Approvals (Complete by Feature Complete Date)

These occur only after GA of this feature is requested (by adding a target:ga label). GA of this feature may not occur until all approvals are obtained.

All Features

[ ] APIs/Externals Externals have been reviewed or N/A. (OpenLiberty/externals-approvers)
- Approver adds label focalApproved:externals
[ ] Demo Demo is scheduled for an upcoming EOI or N/A. (OpenLiberty/demo-approvers)
- Add comment @OpenLiberty/demo-approvers Demo scheduled for EOI [Iteration Number] to this issue.
- Approver adds label focalApproved:demo.
[ ] FAT All Tests complete and running successfully in SOE or N/A. (OpenLiberty/fat-approvers)
- Approver adds label focalApproved:fat.
[ ] Globalization Translation and TVT are complete or N/A. (OpenLiberty/globalization-approvers)
- Approver adds label focalApproved:globalization.

Design Approved Features

[ ] Accessibility Accessibility testing completed or N/A. (OpenLiberty/accessibility-approvers)
- Approver adds label focalApproved:accessibility.
[ ] ID Documentation is complete or N/A. (OpenLiberty/id-approvers)
- Approver adds label focalApproved:id.
- NOTE: If only trivial documentation changes are required, you may reach out to the ID Feature Focal to request a ID Required - Trivial label. Unlike features with regular ID requirement, those with ID Required - Trivial label do not have a hard requirement for a Design/UFO.
[ ] Performance Performance testing is complete or N/A. (OpenLiberty/performance-approvers)
- Approver adds label focalApproved:performance.
[ ] Serviceability Serviceability has been addressed or N/A. (OpenLiberty/serviceability-approvers)
- Approver adds label focalApproved:sve.
[ ] STE Skills Transfer Education chart deck is complete or N/A. (OpenLiberty/ste-approvers)
- Approver adds label focalApproved:ste.
[ ] SVT System Verification Test is complete or N/A. (OpenLiberty/svt-approvers)
- Approver adds label focalApproved:svt.

Remove Beta Fencing (Complete by Feature Complete Date)

[ ] Beta guards are removed, or N/A
- Only after all necessary Focal Point Approvals have been granted.

GA Blog (Complete by Feature Complete Date)

[ ] GA Blog issue created and populated using the Open Liberty GA release blog post template.
- Add a link to the GA Blog issue in the Documents section.
- Note: This is for inclusion into the overall release blog post. If, in addition, you'd also like to create a dedicated blog post about your feature, then follow the "Standalone Feature Blog Post" instructions under the Other Deliverables section.

Post GA

[ ] Replace target:YY00X label with the appropriate release:YY00X. (OpenLiberty/release-manager)
Other Deliverables
[ ] Standalone Feature Blog Post A blog post specifically about your feature or N/A. (OpenLiberty/release-architect)
- This should be strongly considered for larger or more prominent features.
- Follow instructions in the blogs repo.
[ ] OL Guides OL Guides assessment is complete or N/A. (OpenLiberty/guide-assessment)
[ ] Dev Experience Developer Experience & Tools work is complete or N/A. (OpenLiberty/dev-experience-assessment)

mswatosh commented 1 year ago

@njr-11 and I were just discussing the use of synchronized and he mentioned that after Virtual Threads are released synchronized will still block platform threads. We should have a Story to examine uses of synchronized to look for cases where performance could be improved by switching to locks instead.

cbridgha commented 1 year ago

Config tracking issue: https://github.com/OpenLiberty/open-liberty/issues/26000

API/SPI tracking issue: https://github.com/OpenLiberty/open-liberty/issues/25999

idlewis commented 1 year ago

@cbridgha

Notes from the UFO Socialization:

On slide 10, the second example OSGI reference is wrong - fixed (now slide 11)
Slide 16: it would be useful to note that the best performance with VT does not come out of the box, the number of carrier threads needs to be tuned - Added jvm property to Slide 7.
Slide 16: Platforms which have a low limit on the number of platform threads may benefit from using VT (e.g. some z/os environment have a limit of aprox 200 platform threads) - Added to slide (now 17)
Slide 25: enableManagedVT() may need a different name, as it could affect threads other than just managed threads, e.g. EJB timers. Also the behaviour of this API is not yet fully defined. (renamed - and added error state detail... on slide 26)
General: It might be useful to have a slide to address the non-performance advantages of VT, e.g. having one thread per operation (removing thread pooling) could lead do easier management/diagnostics(Added slide 10)
Question was asked if Liberty Component owners should be looking to switch synchronized to J.U.C locks, and also investigate their usage of Thread Local's should be examined - Chuck's response was we don't want to rework all of our synchronized block usage - especially with jvm changes coming in future releases - we should concentrate mainly on scenarios identified ny the performance team, that said, if component owners see areas for improvement, then please proceed.

cbridgha commented 10 months ago

Pending Items before closure: 1) Perf team Blog on VT's. (Dec?) 2) Finish delivering Java 21 VT api fat bucket (Nov)

njr-11 commented 10 months ago

Pending Items before closure:

1. Perf team Blog on VT's. (Dec?)

2. Finish delivering Java 21 VT api fat bucket (Nov)

There is also this item, copied from our slack conversation: "ability to request the Liberty scheduled executor to run a scheduled task on a virtual thread instead of using a pooled platform thread"

bmarwell commented 10 months ago

Does this issue supersede https://github.com/OpenLiberty/open-liberty/issues/21034 ? @Thihup

berndgoetz commented 6 months ago

What's the status of the adoption of Java 21 virtual threads in Open Liberty? Any news, plans, timelines? Thanks in advance!

cbridgha commented 2 months ago

Article: https://www.infoq.com/articles/java-virtual-threads-a-case-study/

scrhartley commented 2 months ago

Article: https://www.infoq.com/articles/java-virtual-threads-a-case-study/

Hopefully this ForkJoinPool fix in JDK 23 will result in improved numbers: https://bugs.openjdk.org/browse/JDK-8322732

OpenLiberty / open-liberty