Occasional "broken pipe" error in ember server

Occasionally, I am getting following error when running wrk on http4s server with ember backend

java.io.IOException: Broken pipe
	at java.base/sun.nio.ch.FileDispatcherImpl.write0(Native Method)
	at java.base/sun.nio.ch.SocketDispatcher.write(Unknown Source)
	at java.base/sun.nio.ch.IOUtil.writeFromNativeBuffer(Unknown Source)
	at java.base/sun.nio.ch.IOUtil.write(Unknown Source)
	at java.base/sun.nio.ch.IOUtil.write(Unknown Source)
	at java.base/sun.nio.ch.UnixAsynchronousSocketChannelImpl.finishWrite(Unknown Source)
	at java.base/sun.nio.ch.UnixAsynchronousSocketChannelImpl.finish(Unknown Source)
	at java.base/sun.nio.ch.UnixAsynchronousSocketChannelImpl.onEvent(Unknown Source)
	at java.base/sun.nio.ch.EPollPort$EventHandlerTask.run(Unknown Source)
	at java.base/sun.nio.ch.AsynchronousChannelGroupImpl$1.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)
	at delay @ fs2.io.net.SocketCompanionPlatform$AsyncSocket.$anonfun$write$1(SocketPlatform.scala:137)
	at async @ fs2.io.net.SocketCompanionPlatform$AsyncSocket.go$2(SocketPlatform.scala:131)
	at flatMap @ fs2.io.net.SocketCompanionPlatform$AsyncSocket.go$2(SocketPlatform.scala:141)
	at modify @ fs2.internal.Scope.close(Scope.scala:262)
	at flatMap @ fs2.Compiler$Target.flatMap(Compiler.scala:162)
	at deferred @ fs2.concurrent.Topic$.apply(Topic.scala:144)
	at acquire @ fs2.Stream.go$11(Stream.scala:1922)

Setup:

• Scala 2.13.8
• Cats Effect 3.3.8
• Fs2 3.2.5
• Http4s 0.23.11

Mentioned error is not logged by logger and is thrown time to time (seems randomly). I wonder what could have caused it? Setup of process running wrk is as follows, wrk opens one connection to http4s server, and 100 instances of wrk script are run in parallel on same linux container. Each wrk process connects to different url path on same server.

[armanbilge]

@retriku do you still have this issue with the latest Cats Effect as well? Seems to me it was the changes in Cats Effect v3.3.8 which caused this behavior and has since been improved. See:

• https://github.com/typelevel/cats-effect/pull/2868 which was released in https://github.com/typelevel/cats-effect/releases/tag/v3.3.8

[FloWi]

Btw: thanks for working on http4s, @armanbilge and others. I really enjoy working with it. The documentation is awesome compared to other open source projects!