HP Caliper 5.3 User Guide (5900-1558, February 2011)

Call Graph Part of the Report
This section reports the call graph produced from the call stack samples. All the call graph
entries—one for each function—are reported. Each entry has one or more lines and delimited by
the line full of dashes.
In each entry, the primary line is the one that starts with an index number in square brackets. The
preceding lines in the entry describe the callers of this function. The lines following the primary
line describe the callees of this function.
The entries are sorted by the number of Sample Hits In or Under Function.
Function Indexes
The Function Indexes is an alphabetical list of each function in your program with its index value.
Avoids gprof Fallacy
The cstack measurement does not exhibit the gprof fallacy condition that the scgprof and
cgprof measurements do. (See “gprof Fallacy and Possibly Misleading Results” (page 131)'.) This
is because the real time of the program that is attributable to a function is directly proportional to
the number of Sample Hits In or Under Function. It does not depend on the number of times a
function is called.
Limitations to Using cstack
• Due to a kernel limitation on HP-UX, call stack sampling on HP-UX 11.23 (v2) exhibits heavy
system call bias, resulting in inaccurate call stack profile reports. For an accurate call stack
profile, you need to run cstack on HP-UX 11.31 (v3)
• You cannot use the caliper diff command with this measurement.
• In programs that dynamically load and then unload shared libraries, the cstack measurement
might not attribute measurement results to the appropriate shared library.
• The kernel does not allow HP Caliper to stop a thread in uninterruptible sleep state. Hence,
if a process has one or more threads in uninterrupible sleep state, the callstack profile may
be inaccurate.
Pstack like functionality
With HP Caliper 5.2, the cstack measurement can be used to generate a pstack-like report.
In this mode, only one callstack sample is collected for all threads of the target process-id. While
reporting, only the callpaths are reported for all the threads; other sections like Function Summary,
Function Details, and CallGraph are not reported.
Specifying 0 with the-e or --duration option will generate this pstack-like report.
For example, the following HP Caliper invocation will collect and report callstack samples for all
threads of the target process '12345':
$ caliper cstack -e 0 12345
A sample report follows:
====================================================================
HP Caliper A.5.1.19 Report Summary for Call Stack Profile
====================================================================
Hot Call Paths (Thread 859899@signal_monitor_thread_main)
-------------------------------------------------------------
--% Total Hits In Only--
Run + Run Block
Index Block Hits Hits Name
Hits Only Only
-------------------------------------------------------------
Avoids gprof Fallacy 149