Performance Implications of Cgo

Using cgo introduces performance overhead due to the cost of crossing the Go/C boundary, garbage collection pauses for C-allocated memory, and the inability of the Go compiler to inline C functions. Every call to a C function (e.g., C.mpz_init) requires a context switch and argument marshaling, which is significantly slower than a native Go function call. To mitigate this, minimize the number of cgo calls by batching operations in C or using runtime.SetFinalizer carefully to avoid excessive GC pressure on Go pointers held by C code.

// Example: Batching reduces cgo call overhead compared to calling C.func per item
func ProcessBatch(items []int) {
    // Single cgo call for the whole batch
    C.process_all(C.int(len(items)), (*C.int)(unsafe.Pointer(&items[0])))
}

Using cgo slows down your program because it forces Go to stop and talk to C code every time you call a function, which is like stopping at a border crossing instead of driving straight through. It also makes memory management harder because Go's automatic cleanup doesn't know about memory C allocated. You should use it only when you absolutely need a C library, and try to make fewer, bigger calls to C instead of many small ones.