![NEW PROFESSIONAL JAVA EVENT KYIV, 2020
Project Valhalla
Inline Types Hierarchy
Source: Tobi Ajila “Welcome to LWorld: The current state of value types in Java “
https://www.youtube.com/watch?v=Xf22I16jVyE&list=LLYgjRSI2oCzI9eooyFrWR7A&index=11
Object
Point?
Point
Nullable Inline Type (Point or null)
Inline Type
Object[]
Point?[]
Point[]](https://image.slidesharecdn.com/projectsvalhallaloomandgraalvmjavafest2020-final1-200601193950/85/JavaFest-Projects-Valhalla-Loom-and-GraalVM-23-320.jpg)
JavaFest. Вадим Казулькин. Projects Valhalla, Loom and GraalVM
- 1. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 NEW PROFESSIONAL JAVA EVENT MARCH 21ST, 2020 KYIV, UKRAINE Vadym Kazulkin Projects Valhalla, Loom and GraalVM
- 2. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Contact Vadym Kazulkin, ip.labs GmbH [email protected] https://www.linkedin.com/in/vadymkazulkin/ @VKazulkin Co-Org Java User Group Bonn and Serverless Bonn Meetup
- 3. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 ip.labs GmbH
- 4. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Agenda • Project Valhalla (Inline Types) • Project Loom (Lightweight Threads and Continuations) • GraalVM
- 5. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Inline Types Source: http://openjdk.java.net/projects/valhalla/
- 6. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Inline types = Value types
- 7. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Goal: • Reboot the layout of data in memory Source: Brian Goetz, Oracle „Evolving the Java Language” https://www.youtube.com/watch?v=A-mxj2vhVAA
- 8. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Motivation: • Hardware has changed • Multi-core • The cost of cache misses has increased Source: Brian Goetz, Oracle „Evolving the Java Language” https://www.youtube.com/watch?v=A-mxj2vhVAA
- 9. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Hardware Memory Model Source: https://www.enterpriseai.news/2014/06/30/shared-memory-clusters-101/
- 10. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Motivation Source: „Latency Numbers Every Programmer Should Know” https://people.eecs.berkeley.edu/~rcs/research/interactive_latency.html
- 11. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Motivation Source: „Latency Numbers Every Programmer Should Know” https://people.eecs.berkeley.edu/~rcs/research/interactive_latency.html
- 12. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Storing objects in the Java Heap has its price, because storing object’s metadata consumes additional memory for : • flags facilitating synchronization/locking • Identity and polymorphismus • garbage collection
- 13. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Inline Types Inline Type is an immutable type that is distinguishable only by the state of its properties
- 14. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Inline Types Immutable: an instance of an inline-type can’t change, once it’s been created Identity-less: inline-types of the same type with the same contents are indistinguishable from each other Flattenable: JVMs are allowed to flatten an inline-type inside of its container Source: Tobi Ajila “Welcome to LWorld: The current state of value types in Java “ https://www.youtube.com/watch?v=Xf22I16jVyE&list=LLYgjRSI2oCzI9eooyFrWR7A&index=11
- 15. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Source: „What Is Project Valhalla?” https://dzone.com/articles/what-is-project-valhalla
- 16. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Benefits: • Reduced memory usage • Reduced indirection • Increased locality Codes like a class, works like a primitive (Brian Goetz)
- 17. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Benefit: Reduced Memory Usage No additional memory to store object metadata, such as flags facilitating synchronization, identity, polymorphismus and garbage collection
- 18. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Benefit: Reduced indirection • Since objects are stored as reference types in Java, each time an object is accessed it must first be dereferenced, causing additional instructions to be executed • The flattened data associated with inline types are immediately present in the location in which they are needed and therefore, require no dereferencing
- 19. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Benefit: Increased locality • Flattened value objects remove indirection which increases the likelihood that values are adjacently stored in memory– especially for arrays or other contiguous memory structures such as classes (i.e. if a class contains inline type fields) • Consequently increases the chance of cache hits, because of hardware prefetch of the cache lines
- 20. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Inline Types inline class Point {long x, y ;}
- 21. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Inline Types Can • have method and field • implement interfaces • use encapsulation • be generic Can’t • be mutated • be sub-classed • be cloned • be Enums Source: Tobi Ajila “Welcome to LWorld: The current state of value types in Java “ https://www.youtube.com/watch?v=Xf22I16jVyE&list=LLYgjRSI2oCzI9eooyFrWR7A&index=11
- 22. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Inline Types Hierarchy Source: Tobi Ajila “Welcome to LWorld: The current state of value types in Java “ https://www.youtube.com/watch?v=Xf22I16jVyE&list=LLYgjRSI2oCzI9eooyFrWR7A&index=11 Object Point? Point Nullable Inline Type (Point or null) Inline Type
- 23. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Inline Types Hierarchy Source: Tobi Ajila “Welcome to LWorld: The current state of value types in Java “ https://www.youtube.com/watch?v=Xf22I16jVyE&list=LLYgjRSI2oCzI9eooyFrWR7A&index=11 Object Point? Point Nullable Inline Type (Point or null) Inline Type Object[] Point?[] Point[]
- 24. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Current Status: • Released public prototype LW2 • Can declare and use inline types (inline classes) • No support for generics yet List<Point> // compilation error • No support for specialized generics (Point<T>) • No Support for migration of existing classes (like Optional) • Memory Layout optimizations implemented • Compiler/Virtual Machine optimizations implemented • A lot of challenges to solve (read the article https://www.infoq.com/news/2019/07/valhalla-openjdk-lw2-released/) Source: Brian Goetz, Oracle „Valhalla Update” https://www.youtube.com/watch?v=1H4vmT-Va4o
- 25. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla Open Questions: • Migration of existing classes (Option, LocaDateTime) to inline classes • Nullity • Equality • GraalVM Support • How Java type system should look like Source: Brian Goetz, Oracle „Valhalla Update” https://www.youtube.com/watch?v=1H4vmT-Va4o
- 26. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Valhalla How Java type system should look like ? Source: Tobi Ajila “Welcome to LWorld: The current state of value types in Java “ https://www.youtube.com/watch?v=Xf22I16jVyE&list=LLYgjRSI2oCzI9eooyFrWR7A&index=11 Object ValObject Inline Types RefObject References
- 27. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Lightweight Thread and Continuations Source: http://openjdk.java.net/projects/loom
- 28. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Lightweight Threads = Fibers Lightweight Threads = Virtual Threads in the newest prototype?
- 29. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Motivation: Developers currently have 2 choices to write concurrent code: • use blocking/synchronous API, which is simple, but less scalable (number of threads, that OS supports is far less that open and concurrent connections required) • asynchronous API (Spring Project Reactor, RXJava 2), which is scalable, but complex, harder to debug and profile and limited (no asynchronous JDBC standard in this area) Sources: Alan Bateman, Oracle „Project Loom: Fibers and Continuations for Java” https://www.youtube.com/watch?v=vbGbXUjlRyQ
- 30. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Goal: To write simple and scalable code
- 31. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Lightweight Thread Lightweight thread scheduled not by the OS, but by the Java Runtime with low memory footprint and low task-switching cost
- 32. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Continuation Continuation is a program object, representing a computation that may be suspended and resumed
- 33. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Continuation package java.lang; public class Continuation { public Continuation (ContinuationScope scope, Runnable target) public final void run() public static void yield (ContinuationScope scope) public boolean isDone() }
- 34. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Continuations example () { var scope = new ContinuationScope(„Example_Scope“); var continuation = new Continuation (scope, () -> { out.print(„1“); Continuation.yield(scope); out.print(„2“); Continuation.yield(scope); out.print(„3“); Continuation.yield(scope); }); while (! continuation.isDone()) { out.print(„ run.. “); continuation.run(); } } Output: run.. 1 run.. 2 run.. 3
- 35. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Lightweight Thread & Continuations Thread = Continuation + Schedular
- 36. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Schedular Schedular executes the task on a pool of carrier threads • java.util.concurrent.Executor API exposes the Schedular • Default schedular is a ForJoinPool Source: Alan Bateman, Oracle „Project Loom Update” https://www.youtube.com/watch?v=NV46KFV1m-4
- 37. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Lightweight Thread Implementation • Currently Thread and Lightweight Thread don’t have a common supertype • Thread.currentThread() in context of Lightweight Thread • Creates adaptor (Shadow Thread) • Adaptor emulates legacy Thread API (except deprecated methods like stop, suspend and resume) • Thread Local becomes Lightweight Thread Local Source: Alan Bateman, Oracle „Project Loom Update” https://www.youtube.com/watch?v=NV46KFV1m-4
- 38. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Structured Concurrency Basic idea: Everytime that the control splits into multiple concurrent paths, we want to guarantee that they join up again try (var scope= ThreadScope. open()) { scope.schedule(task1); scope.schedule(task2); } //blocks until task1 and task2 terminate Sources: Nathanial J. Smith „Notes on structured concurrency, or: Go statement considered harmful” https://vorpus.org/blog/notes-on-structured-concurrency-or-go-statement-considered-harmful/ Roman Elizarov: “Structured concurrency with Coroutines in Kotlin” https://medium.com/@elizarov/structured-concurrency-722d765aa952
- 39. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Structured Concurrency Cancelation: • Each Lightweight Thread has cancel status which can only be set once, which sets the interrupt status and unparks the Lightweight Thread • The task can poll canceled status try (var scope= ThreadScope. open(PROPAGATE_CANCEL)) { scope.schedule(task1); scope.schedule(task2); } //canceling the lightweight thread executing this code will task1 and task2 Source: Alan Bateman, Oracle „Project Loom Update” https://www.youtube.com/watch?v=NV46KFV1m-4
- 40. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Lightweight Thread Current Status: • Lightweight Thread currently supports: • scheduling • parking/unparking • waiting for a Lightweight Thread to terminate • Lightweight Thread -friendly APIs • java.util.concurrent Locks • java.net.Socket/ServerSocket (since JDK 13) • java.nio.channels.SocketChannel and Pipes (since JDK 11) • Thread.sleep • JSSE implementation of TLS • AccessControl.doPrivileged (since JDK 12) Source: Ron Pressler, Project Loom: Helping Write Concurrent Applications on the Java Platform https://www.youtube.com/watch?v=lIq-x_iI-kc
- 41. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Current Status: • Implemented initial prototype with Continuation and Lightweight Thread support • Current prototype of Continuations and Lightweight Thread can run existing code • Debugger Support Current focus on: • Performance improvement • Stable Lightweight Thread API • Java Flight Recorder support Source: Alan Bateman, Oracle „Project Loom Update” https://www.youtube.com/watch?v=NV46KFV1m-4
- 42. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Limitations: • Can‘t yield with native frames Further Work: • java.net.InetAddress • Console I/O • File I/O
- 43. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Loom Open Questions: • Should the existing Thread API be completely re-examined? • Can all existing code be run on top of Lightweight Threads?
- 44. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Polyglot GraalVM Source: http://openjdk.java.net/projects/metropolis
- 45. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Project Metropolis Goals: • Low footprint ahead-of-time mode for JVM-based languages • High performance for all languages • Convenient language interoperability and polyglot tooling Source: „Everything you need to know about GraalVM by Oleg Šelajev & Thomas Wuerthinger” https://www.youtube.com/watch?v=ANN9rxYo5Hg
- 46. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 JEP 317 Experimental Java-Based JIT Compiler Graal, a Java-based JIT compiler on the Linux/x64 platform, is the basis of the experimental Ahead-of-Time (AOT) compiler introduced in JDK 9. To Enable: -XX:+UnlockExperimentalVMOptions -XX:+UseJVMCICompiler
- 47. NEW PROFESSIONAL JAVA EVENT KYIV, 2020
- 48. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM Architecture Sources: Practical Partial Evaluation for High-Performance Dynamic Language Runtimes http://chrisseaton.com/rubytruffle/pldi17- truffle/pldi17-truffle.pdf „The LLVM Compiler Infrastructure“ https://llvm.org/
- 49. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM Benchmarks Sources: Renaissance Suite https://renaissance.dev/
- 50. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM libgraal Library Sources: „libgraal: GraalVM compiler as a precompiled GraalVM native image“ https://medium.com/graalvm/libgraal-graalvm-compiler-as-a-precompiled-graalvm-native-image-26e354bee5c libgraal jargraal • libgraal is a shared library, produced by GraalVM Native Image with a pre-compiled version of the GraalVM compiler • In Java applications on GraalVM libgraal used as the top tier Just-In-Time compiler • libgraal improves startup
- 51. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM Architecture Sources: Practical Partial Evaluation for High-Performance Dynamic Language Runtimes http://chrisseaton.com/rubytruffle/pldi17- truffle/pldi17-truffle.pdf „The LLVM Compiler Infrastructure“ https://llvm.org/
- 52. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 SubstrateVM Source: Oleg Šelajev, Thomas Wuerthinger, Oracle: “Deep dive into using GraalVM for Java and JavaScript” https://www.youtube.com/watch?v=a-XEZobXspo
- 53. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM and SubstrateVM Source: Oleg Selajev, Oracle : “Run Code in Any Language Anywhere with GraalVM” https://www.youtube.com/watch?v=JoDOo4FyYMU
- 54. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM on SubstrateVM A game changer for Java & Serverless? Cold Start : Source: Ajay Nair „Become a Serverless Black Belt” https://www.youtube.com/watch?v=oQFORsso2go
- 55. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 AWS Lambda cold start time by supported language Source: Yan Cui: https://read.acloud.guru/does-coding-language-memory-or-package-size-affect-cold-starts-of-aws-lambda-a15e26d12c76
- 56. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM on SubstrateVM A game changer for Java & Serverless? Java Function compiled into a native executable using GraalVM on SubstrateVM reduces • “cold start” times • memory footprint by order of magnitude compared to running on JVM. And both memory and execution time are cost dimension, when using Serverless in the cloud
- 57. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM on SubstrateVM A game changer for Java & Serverless? Current challenges native executable using GraalVM : • Most Cloud Providers (AWS) doesn’t provide GraalVM as Java Runtime out of the box, only Open JDK (e.g. AWS provides Corretto) • Some Cloud Providers (AWS) provide Custom Runtime Option • Docker Image with GraalVM instead of Open JDK • Frameworks like Micronaut and Quarkus which provide tooling for generating Custom Runtime for cloud providers
- 58. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM Complitation Modes Source: „Everything you need to know about GraalVM by Oleg Šelajev & Thomas Wuerthinger” https://www.youtube.com/watch?v=ANN9rxYo5Hg
- 59. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 AOT vs JIT Source: „Everything you need to know about GraalVM by Oleg Šelajev & Thomas Wuerthinger” https://www.youtube.com/watch?v=ANN9rxYo5Hg
- 60. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 Support of GraalVM native images in Frameworks • Spring Framework: working toward GraalVM native image support without requiring additional configuration or workaround is one of the themes of upcoming Spring Framework 5.3 • Spring Boot: Ongoing work on experimental Spring Graal Native project. Probably ready for the 2.4 release • Quarkus: a Kubernetes Native Java framework developed by Red Hat tailored for GraalVM and HotSpot, crafted from best-of-breed Java libraries and standards. • Micronaut: a modern, JVM-based, full-stack framework for building modular, easily testable microservice and serverless applications. Source: „GraalVM native image support“ https://github.com/spring-projects/spring-framework/wiki/GraalVM-native-image-support
- 61. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 GraalVM Current State Source: „Everything you need to know about GraalVM by Oleg Šelajev & Thomas Wuerthinger” https://www.youtube.com/watch?v=ANN9rxYo5Hg
- 62. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 is still an interesting and great programming language
- 63. NEW PROFESSIONAL JAVA EVENT KYIV, 2020
- 64. NEW PROFESSIONAL JAVA EVENT KYIV, 2020 www.iplabs.de Thank You!