When I run my benchmarks with go test -v -bench=. -benchmem, I see the following results.
go test -v -bench=. -benchmem
f1 10000 120860 ns/op 2433 B/op
allocs/op means how many distinct memory allocations occurred per op (single iteration).
allocs/op
B/op is how many bytes were allocated per op.
B/op