ThreadingModel.VirtualThread significant performance drop.

[sanIncredible]

Questions

Version

4.5.8

Context

while running existing application with ThreadingModel.VirtualThread , application performance dropped significantly.

Do you have a reproducer?

Yes

Steps to reproduce

1. deploy a verticle containing HTTP server , responding every request wuth 200-OK
2. first execute with ThreadinModel.EventLoop
3. execute with ThreadingModel.VirtualThread
4. run http load test.

EventLoop model results : 31000 request per second Virtual Thread model results : 811 request per second.

CPU utilization is very less in VT model ,

Extra

• Anything that can be relevant such as OS version, JVM version

• openJdk 21

[vietj]

can you share your entire benchmark @sanIncredible without it, those numbers don't mean a lot

[sanIncredible]

not sure if these would help , cant upload whole JFR due to organization policy.

[vietj]

that does not help a lot, can you provide a small project that reproduces it ? like a minimalistic HTTP server with vertx and a client

[sanIncredible]

`

public class BootStrapp{

public static Vertx getVertx(){

}

private static Vertx vertx;

public static void main(String [] args){ vertx = Vertx.vertx(); DepolymentOptions options = new DeploymentOptions(). setThreadingModel(ThreadingModel.VIRTUAL_THREAD; //setThreadingModel(ThreadingModel.EVENT_LOOP;

vertx.deployVerticle(MainVerticle.class.getName(),options,res->{ if(res.failed()){ } else{

}

});

} }

public class MainVerticle extends AbstractVerticle{ @Override public void start(Promise startPromise) throws Exception {

Vertx vertx = BootStrapp.getVertx(); Router router = Router.router(vertx);

router.route().handler(BodyHandler.create());

router.get("/getDemo/").handler(this::getHandler);

vertx.createHttpServer().requestHandler(event->router.handle(event)).listen(8890,"127.0.0.1",result->{ if(result.succeeded()){ startPromise.tryComplete(); } else{ startPromise.fail(result.cause()); } });

}

private void getHandler(RoutingContext context) context.response().setStatusCode(201).end(); }

`

Client used :: https://nghttp2,org/documentation/h2load-howto.html

[sanIncredible]

This call sequence is not there in Eventloop model. is this causing performance issue ?