Go pprof broken?

1test.go

package main

import (
	"fmt"
	"os"
	"runtime/pprof"
)

func main() {
	f, err := os.Create("test.pprof")
	if err != nil {
		panic(err)
	}

	defer f.Close()

	err = pprof.StartCPUProfile(f)
	if err != nil {
		panic(err)
	}

	defer pprof.StopCPUProfile()

	for i := 0; i < 10000000; i++ {
		fmt.Sprintf("at: %d", i)
	}
}

2output.txt

5.76s of 5.76s total (  100%)
      flat  flat%   sum%        cum   cum%
     5.76s   100%   100%      5.76s   100%  
(pprof) list
Total: 5.76s
(pprof) raw
PeriodType: cpu nanoseconds
Period: 10000000
Samples:
samples/count cpu/nanoseconds
          2   20000000: 1 2 
        558 5580000000: 3 2 
          1   10000000: 4 5 6 7 8 
          1   10000000: 9 10 6 7 8 
          1   10000000: 11 12 
          3   30000000: 1 12 
          2   20000000: 3 12 
          3   30000000: 13 2 
          1   10000000: 14 2 
          3   30000000: 15 12 
          1   10000000: 16 12 
Locations
     1: 0x3a7ab 
     2: 0x31a90 
     3: 0x3a77b 
     4: 0x3e52e 
     5: 0x3ea73 
     6: 0x222f 
     7: 0x14a62 
     8: 0x39d40 
     9: 0x3e593 
    10: 0x3eafa 
    11: 0x2429b 
    12: 0x31ad0 
    13: 0x39d8e 
    14: 0x19f8e 
    15: 0x3a64c 
    16: 0x242b4 
Mappings
(pprof) exit