HP Caliper User Guide Release 5.5 (5900-2351, August 2012)

Diagnostic Messages
The Diagnostic Messages appear at the end of the report.
gprof Fallacy and Possibly Misleading Results
The HP Caliper sampled call graph report (with the scgprof measurement) and the call graph
report (with the cgprof measurement) both produce gprof-like reports. Thus, both these reports
might produce misleading results regarding the amount of time spent under a function. The
inaccuracy results because the HP Caliper sampled call graph and call graph reports estimate the
amount of time spent in a function from the number of times the function is called, regardless of
the time actually spent in the function. This is sometimes referred to as the gprof fallacy.
For example, if function A and B each call function C 10 times, scgprof and cgprof assign the
total time spent in function C equally to both functions A and B. However, calls from function A
might take longer than those from function B. In this example, function A would have a higher
effect on performance than function B, which the call graph data would not show.
Keep this limitation in mind when you analyze sampled call graph and call graph report results.
132 Producing a Sampled Call Graph Profile Analysis