Why Does an Infinite Loop Goroutine Block a Go HTTP Server?

Issue: Infinite-Loop Goroutine Blocking HTTP Server

In Go, infinite-loop goroutines are expected to block other goroutines when using less threads than available cores, even if runtime.GOMAXPROCS is set accordingly. However, this behavior differs when utilizing the net/http package.

Q: Why does an infinite-loop goroutine block the HTTP server after a few invocations?

A: The Go runtime's scheduler is not fully pre-emptive. In your example, the infinite loop contains no function calls, preventing the scheduler from interveneing. This results in continuous handling of the loop by one thread, blocking other goroutines, including the HTTP server.

Q: Why does runtime.LockOSThread() fail to resolve the issue?

A: runtime.LockOSThread() is intended to ensure that the empty loop runs in a separate thread. However, the scheduler's non-preemptive nature renders this approach ineffective in this case.

Resolution:

• Introduce a non-empty loop body to trigger function calls and allow the scheduler to intervene.
• Manually call runtime.Gosched within the infinite loop to explicitly yield the processor.

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