how caliper measures code region runtime?

[twang15]

Using caliper instrumentation to measure end-to-end runtime, I am confused by the following 2 cases.

Suppose the program is instrumented as following:

main()
{
cali_begin_string_byname('loop', 'main')
..

cali_begin_string_byname('loop', 'loop1')
loop1 code
cali_end_byname('loop')

...
cali_begin_string_byname('loop', 'loop2')
loop1 code
cali_end_byname('loop')
..
cali_end_byname('loop')
}

After data collection, I process the data with
cali-query -s time.inclusive.duration --table a.cali

My expectation is that aggregation of caliper entry "main" should be the end-to-end runtime.
But, I observe two cases:

1. for some apps, the result is as expected. The entries are like:
   main
   main/loop1
   main/loop2

2. for others, there is no "main" entry, but only entries like
   main/loop1
   main/loop2

I am not sure why I see the differences between case 1 and case 2.
Could anyone explain this?

[daboehme]

Are you sure the cali_end_byname() at the end of the main loop is there and being executed?

[twang15]

Yes, it is executed.

Does cali_end_byname have to immediately follow a loop?
For example, in the following code snippet, function foo does not have a loop.
Will caliper time function foo properly?

cali_begin_by_string('foo', 'function1')
call foo()
cali_end_byname('foo')