[Wasm][Threading] Task.Delay only continues after a GC

[jeromelaban]

Description

Given a Wasm Threads enabled runtime, using Task.Delay waits for the next GC to continue.

Reproduction Steps

Given a Wasm Threads enabled runtime, and the following code:

static void Main()
{
    Console.WriteLine($"Runtime Version: " + RuntimeInformation.FrameworkDescription);
    Console.WriteLine($"Runtime Mode: " + runtimeMode);
    Console.WriteLine($"TID: {Thread.CurrentThread.ManagedThreadId}");

    Bug01();
}

private static void Bug01()
{
    Timer t = new Timer(_ =>
    {
        Log($"Before GC");
        GC.Collect();
        Log($"After GC");
    });
    t.Change(5000, 0);

    Log($"-> Bug01");
    Task.Run(async () =>
    {
        var sw = Stopwatch.StartNew();
        Log($"Before 2000ms delay");
        await Task.Delay(2000);
        Log($"After delay {sw.ElapsedMilliseconds}");
    });
    Log($"<- Bug01");

    void Log(string message) => Console.WriteLine($"[TID:{Thread.CurrentThread.ManagedThreadId}] {message}");
}

Shows the following

Expected behavior

The Async method continues after about 2 seconds, not when the GC has been invoked.

Actual behavior

Runtime Version: .NET 7.0.0-dev
dotnet.js:12 Runtime Mode: InterpreterAndAOT
dotnet.js:12 TID: 1
dotnet.js:12 [TID:1] -> Bug01
dotnet.js:12 [TID:1] <- Bug01
dotnet.js:12 [TID:2] Before 2000ms delay
dotnet.js:12 
       Blocking on the main thread is very dangerous, see https://emscripten.org/docs/porting/pthreads.html#blocking-on-the-main-browser-thread
dotnet.js:12 [TID:2] Before GC
dotnet.js:12 [TID:1] After delay 5690
dotnet.js:12 [TID:2] After GC

Regression?

no

Known Workarounds

none

Configuration

be4d292

Other information

No response

[ghost]

Tagging subscribers to this area: @mangod9
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Given a Wasm Threads enabled runtime, using Task.Delay waits for the next GC to continue.

Reproduction Steps

Given a Wasm Threads enabled runtime, and the following code:

static void Main()
{
    var runtimeMode = Environment.GetEnvironmentVariable("UNO_BOOTSTRAP_MONO_RUNTIME_MODE");
    Console.WriteLine($"Runtime Version: " + RuntimeInformation.FrameworkDescription);
    Console.WriteLine($"Runtime Mode: " + runtimeMode);
    Console.WriteLine($"TID: {Thread.CurrentThread.ManagedThreadId}");

    Bug01();
}

private static void Bug01()
{
    Timer t = new Timer(_ =>
    {
        Log($"Before GC");
        GC.Collect();
        Log($"After GC");
    });
    t.Change(5000, 0);

    Log($"-> Bug01");
    Task.Run(async () =>
    {
        var sw = Stopwatch.StartNew();
        Log($"Before 2000ms delay");
        await Task.Delay(2000);
        Log($"After delay {sw.ElapsedMilliseconds}");
    });
    Log($"<- Bug01");

    void Log(string message) => Console.WriteLine($"[TID:{Thread.CurrentThread.ManagedThreadId}] {message}");
}

Shows the following

Expected behavior

The Async method continues after about 2 seconds, not when the GC has been invoked.

Actual behavior

Runtime Version: .NET 7.0.0-dev
dotnet.js:12 Runtime Mode: InterpreterAndAOT
dotnet.js:12 TID: 1
dotnet.js:12 [TID:1] -> Bug01
dotnet.js:12 [TID:1] <- Bug01
dotnet.js:12 [TID:2] Before 2000ms delay
dotnet.js:12 
       Blocking on the main thread is very dangerous, see https://emscripten.org/docs/porting/pthreads.html#blocking-on-the-main-browser-thread
dotnet.js:12 [TID:2] Before GC
dotnet.js:12 [TID:1] After delay 5690
dotnet.js:12 [TID:2] After GC

Regression?

no

Known Workarounds

none

Configuration

be4d292

Other information

No response

Author:	jeromelaban
Assignees:	-
Labels:	area-System.Threading
Milestone:	-

[ghost]

Tagging subscribers to 'arch-wasm': @lewing
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Given a Wasm Threads enabled runtime, using Task.Delay waits for the next GC to continue.

Reproduction Steps

Given a Wasm Threads enabled runtime, and the following code:

static void Main()
{
    Console.WriteLine($"Runtime Version: " + RuntimeInformation.FrameworkDescription);
    Console.WriteLine($"Runtime Mode: " + runtimeMode);
    Console.WriteLine($"TID: {Thread.CurrentThread.ManagedThreadId}");

    Bug01();
}

private static void Bug01()
{
    Timer t = new Timer(_ =>
    {
        Log($"Before GC");
        GC.Collect();
        Log($"After GC");
    });
    t.Change(5000, 0);

    Log($"-> Bug01");
    Task.Run(async () =>
    {
        var sw = Stopwatch.StartNew();
        Log($"Before 2000ms delay");
        await Task.Delay(2000);
        Log($"After delay {sw.ElapsedMilliseconds}");
    });
    Log($"<- Bug01");

    void Log(string message) => Console.WriteLine($"[TID:{Thread.CurrentThread.ManagedThreadId}] {message}");
}

Shows the following

Expected behavior

The Async method continues after about 2 seconds, not when the GC has been invoked.

Actual behavior

Runtime Version: .NET 7.0.0-dev
dotnet.js:12 Runtime Mode: InterpreterAndAOT
dotnet.js:12 TID: 1
dotnet.js:12 [TID:1] -> Bug01
dotnet.js:12 [TID:1] <- Bug01
dotnet.js:12 [TID:2] Before 2000ms delay
dotnet.js:12 
       Blocking on the main thread is very dangerous, see https://emscripten.org/docs/porting/pthreads.html#blocking-on-the-main-browser-thread
dotnet.js:12 [TID:2] Before GC
dotnet.js:12 [TID:1] After delay 5690
dotnet.js:12 [TID:2] After GC

Regression?

no

Known Workarounds

none

Configuration

be4d292

Other information

No response

Author:	jeromelaban
Assignees:	-
Labels:	arch-wasm, area-System.Threading
Milestone:	7.0.0

[kg]

Fixed by #70863