Runtime Internals Checkpoint

Stack growth, scheduler behavior, and escape analysis implications.

Get every question correct to pass this checkpoint. You can review feedback, revise your answers, and submit again.

1. A service stores the only copy of required business state in sync.Pool. After GC a Get returns nil. What design assumption failed?

Select one answer.

Pool retention was treated as a correctness guarantee GC must be disabled whenever Pool is used Get is guaranteed to return the most recently put item Pool entries are durable if only one goroutine accesses them

2. Returning a pointer to a local variable is correct Go, but a benchmark now allocates. What evidence should you inspect before changing the API?

Select one answer.

Assume every local pointer remains on a fixed goroutine stack Treat all uses of generics as the cause Compiler escape diagnostics and allocation measurements for the actual build Infer heap placement only from the variable name

3. A recursive hot path slows at greater depth without a correctness failure. Which explanation is plausible enough to measure?

Select one answer.

Additional frames can require goroutine stack growth Goroutine stacks must have a compile-time fixed size The program must be using operating-system processes instead of goroutines Recursion always allocates one heap object per call

4. A cache changes from holding 20-byte views of 4 MiB request buffers to owning 20-byte copies. Allocation count rises. What should be measured before rejecting the change?

Select one answer.

Only source line count Retained heap at the same cache population, alongside time and allocation cost Whether generic constraints look narrower Only the number of goroutines

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