xref: /netbsd-src/external/cddl/dtracetoolkit/dist/Examples/php_flowinfo_example.txt (revision c29d51755812ace2e87aeefdb06cb2b4dac7087a)
1The following are examples of php_flowinfo.d.
2
3This is a simple script to trace the flow of PHP functions.
4Here it traces the example program, Code/Php/func_abc.php
5
6# php_flowinfo.d
7C    PID/TID   DELTA(us)              FILE:LINE TYPE     -- FUNC
80  18422/1             9      func_abc.php:22   func     -> func_a
90  18422/1            35      func_abc.php:18   func       -> sleep
100  18422/1       1009146      func_abc.php:18   func       <- sleep
110  18422/1            35      func_abc.php:19   func       -> func_b
120  18422/1            24      func_abc.php:11   func         -> sleep
130  18422/1       1009803      func_abc.php:11   func         <- sleep
140  18422/1            34      func_abc.php:12   func         -> func_c
150  18422/1            24      func_abc.php:5    func           -> sleep
160  18422/1       1009953      func_abc.php:5    func           <- sleep
170  18422/1            28      func_abc.php:6    func         <- func_c
180  18422/1            11      func_abc.php:13   func       <- func_b
190  18422/1            10      func_abc.php:20   func     <- func_a
20^C
21
22The third column is indented by 2 spaces to show when a new function begins.
23This shows which function is calling which - the output above begins by
24showing that func_a() began; slept, and returned from sleep; and then called
25func_b().
26
27The DELTA(us) column shows time from that line to the previous line, and
28so can be a bit tricky to read. For example, the second line of data output
29(skipping the header) reads as "the time from func_a() beginning to
30calling the sleep function beginning was 35 microseconds".
31
32The LINE column shows the line in the file what was being executed. Refer
33to the source program to see what this line refers to.
34
35If the output looks shuffled, check the CPU "C" column - if it changes,
36then the output is probably shuffled. See Notes/ALLsnoop_notes.txt for
37details and suggested workarounds.
38
39See Notes/ALLflow_notes.txt for important notes about reading flow outputs.
40
41