**************************************************************************
* Notes for all scripts that print inclusive function times (or method,
* or subroutine).
*
* $Id: ALLinclusive_notes.txt,v 1.1.1.1 2015/09/30 22:01:08 christos Exp $
*
* COPYRIGHT: Copyright (c) 2007 Brendan Gregg.
**************************************************************************
* What is "inclusive" function time?
This is the time of function execution, from when the function begins to
when it completes. This includes the times from all child functions called.
Inclusive function time is calculated in a very simple way,
inclusive function time = time(function end) - time(function start)
Consider this Bourne shell program,
1 #!./sh
2
3 func_c()
4 {
5 echo "Function C"
6 sleep 1
7 }
8
9 func_b()
10 {
11 echo "Function B"
12 sleep 1
13 func_c
14 }
15
16 func_a()
17 {
18 echo "Function A"
19 sleep 1
20 func_b
21 }
22
23 func_a
func_a() calls func_b() which calls func_c(). Tracing the flow using
sh_flowtime.d shows,
# ./sh_flowtime.d | cat -n
1 C TIME(us) FILE DELTA(us) -- NAME
2 0 3052991099265 func_abc.sh 2 -> func_a
3 0 3052991099324 func_abc.sh 59 > echo
4 0 3052992111638 func_abc.sh 1012314 | sleep
5 0 3052992111678 func_abc.sh 39 -> func_b
6 0 3052992111729 func_abc.sh 51 > echo
7 0 3052993121633 func_abc.sh 1009903 | sleep
8 0 3052993121693 func_abc.sh 60 -> func_c
9 0 3052993121745 func_abc.sh 52 > echo
10 0 3052994131634 func_abc.sh 1009888 | sleep
11 0 3052994131685 func_abc.sh 50 <- func_c
12 0 3052994131699 func_abc.sh 14 <- func_b
13 0 3052994131707 func_abc.sh 7 <- func_a
the output of DTrace was piped through "cat -n" to enumerate the lines.
Inclusive function time for func_a() in the above output would be the
time from line 2 to line 13. This inclusive time includes the time
for both func_b() and func_c().
Looking back at the code, inclusive time for func_a() is the time spent
in code lines 18, 19 and 20.
See Notes/ALLexclusive_notes.txt for details on "exclusive" function time.