Error calling with java a exported function by eta in a multi-thread environment

Description

I want to export a function like this:

foreign export java "@static eta.example.MyClass.sayAnything" sayAnythingEta :: String -> IO ()
sayAnythingEta text = do
putStrLn text
return text

How can I call it in java. Further more, how call I call it in java multi-thread mode.

I try to run it in java multi-thread environment, then I got exceptions:

Exception in thread "pool-1-thread-5" eta.runtime.exception.EtaException: thread blocked indefinitely in an MVar operation
at eta.runtime.stg.Capability.detectMVarDeadlock(Capability.java:703)
at eta.runtime.stg.Capability.idleLoop(Capability.java:690)
at eta.runtime.stg.Capability.blockedLoop(Capability.java:728)
at eta.runtime.stg.Capability.blockedLoop(Capability.java:724)
at eta.runtime.concurrent.Concurrent.takeMVar(Concurrent.java:71)
at base.ghc.io.handle.Internals$$wa2.call(Internals.hs:164)
at base.ghc.io.handle.Internals$a3.applyV(Internals.hs:133)
at eta.runtime.exception.Exception.maskAsyncExceptions(Exception.java:42)
at base.ghc.io.handle.Internals$$wa4.call(Internals.hs:131)
at base.ghc.io.handle.Internals$$wa3.call(Internals.hs:237)
at base.ghc.io.handle.Internals$wantWritableHandle1.call(Internals.hs:227)
at base.ghc.io.handle.Text$hPutStr2.call(Text.hs:544)
at main.Main$$fe_sayHelloEta1.call(Main.hs:10)
at main.Main$$fe_sayHelloEta.call(Main.hs:9)
at main.Main$$fe_sayHelloEta.applyV(Main.hs:9)
at eta.runtime.stg.Closures$EvalIO.enter(Closures.java:177)
at eta.runtime.stg.Capability.schedule(Capability.java:246)
at eta.runtime.stg.Capability.scheduleClosure(Capability.java:202)
at eta.runtime.Runtime.evalIO(Runtime.java:400)
at eta.example.Duckling.sayHello(Unknown Source)
at Main$1.run(Main.java:18)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

Please help me!

Hi! I think you have made a typo in your example, i suppose it is:

foreign export java "@static eta.example.MyClass.sayAnything" sayAnythingEta :: String -> IO ()
sayAnythingEta text = do
  putStrLn text
  return ()

I've just test something similar with lastest etlas and eta and it worked for me.
What do you mean with "java multi-thread environment"?

@jneira

@jneira Hello, jneira, thank you for your answer. Actually, my program is multi-threaded, I want to call this function in multi-threaded state. Just like this:

public static void main(String[] args) {
        ThreadPoolExecutor threadPool = (ThreadPoolExecutor) Executors.newFixedThreadPool(100);

        long t0 = System.currentTimeMillis();

        for (int i = 0; i < 10; i++) {
            threadPool.execute(new Thread() {
                @Override
                public void run() {
                     eta.example.MyClass.sayAnything("Hello eta.");
                }
            });
        }

        threadPool.shutdown();
        try {
            threadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        long t1 = System.currentTimeMillis();

        System.out.println("Time: " + (t1 - t0));
}

How can I achieve this?

@rahulmutt

I've reproduced the error in a test project: https://github.com/jneira/eta-test/blob/print-ffi/java/Utils.java#L47-L71
It may be a bug in the runtime (maybe @rahulmutt could confirm it)

@rahulmutt

@rahulmutt Is there any solution to this problem?

Navigation Menu

Repository navigation

Error calling with java a exported function by eta in a multi-thread environment #979

Description

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Error calling with java a exported function by eta in a multi-thread environment #979

Description

Description

Activity

jneira commented on Oct 27, 2019

Boreaso commented on Oct 28, 2019

jneira commented on Oct 30, 2019

Boreaso commented on Oct 30, 2019

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions